The physiological components altered by training are: (a) the ATP and CP stores in the muscles, (b) the amount of glycogen (stored in the muscles and liver) and blood glucose that can be used, (c) the activity of the glycolytic enzymes in the muscles, and (d) the ability of the body to buffer (tolerate) higher levels of lactic acid.
Training the lactacid energy system is also necessary. Its improvement is best achieved by experiencing 100 percent effort levels at training. However, such training is particularly exhausting and its repetition will be governed by the rate of recovery between training stimuli. In order to experience a sufficient number of skill repetitions so that efficiency of movement can be learned, ultra-short training would seem to be the most appropriate form of conditioning. The ceiling level of training for these two energy (alactic and lactic) systems can be achieved in a relatively short time (from five to seven weeks)
For sprinting: The development of a general endurance capacity would also increase the ability of an athlete to recover more quickly between repetitions of training stimuli and to perform greater training volumes. However, if that endurance capacity is developed using the same activity as the event itself it could be counter productive (e.g., endurance running reduces the capacity to sprint)
Sustained Events (60 seconds to 60 minutes)
The greatest proportion of energy in these events is contributed by the aerobic energy system. At various stages during and often at the end of an event high lactic acid levels can be incurred. If they occur during the event there usually needs to be some recovery period to return lactic acid to tolerable levels (normally 4 mM or less). In sustained cyclic events such as running, swimming, cycling, and cross-country skiing, there is an exaggerated use of the lactacid energy system at the start and end of the event. There is also some exploitation of the alactacid energy system but its overall contribution to such an extended performance is virtually negligible. Thus, performance improvements through physical training should come from the aerobic and, to a lesser extent, the anaerobic energy systems.
(a) Aerobic power can be improved by 5 to 20 percent depending upon the initial fitness level of the athlete. Even an improvement of five percent is of greater influence when compared to what can be contributed by the lactacid energy system. Thus, the principal emphasis of training should be on aerobic adaptation which will produce marked changes in the physiological structure and capacity of an individual.
(b) The lactacid system is influenced by the original strength of the individual. Theory suggests that the greater the strength of a person, the fewer the number of fibers that need to be contracted to perform a certain level of work (this means the less anaerobic work that needs to be performed per standard unit of performance). Alternatively, a higher working capacity can be maintained if a stronger individual is required to perform at a standard effort level. This contention may be true when general training is initiated but it probably is not relevant once specific training commences. It is best to plan to achieve strength improvements before starting specific training for these events.
aerobic capacity (usually measured through maximum oxygen uptake--VO2max) can be increased by as much as 20 percent depending upon the initial level of fitness and the use of graded-stepped overloads as training stimuli. On the other hand, the better the initial level of aerobic fitness, the less it will contribute to performance improvements.
Some of the major adaptations that occur through aerobic training are: (a) increased tone of peripheral veins; (b) greater contractility in the heart (it can pump more forcefully); (c) increased stroke volume (more blood is pumped per beat); (d) more effective blood flow distribution between active and inactive muscles, (e) increased mass in the heart muscle (it has better endurance capabilities by having more muscle to pump longer); and (f) the number and size of mitochondria are increased within each working muscle which facilitates a greater use of oxygen to produce ATP.
Enzymatic increases that occur within the mitochondria as a result of aerobic endurance training are as follows: 1) those associated with the Kreb's cycle and respiratory chain; 2) those associated with the shuttle systems that transfer protons developed through glycolysis into the mitochondria for use in the respiratory chain; and 3) those associated with fatty acid metabolism (by 200 to 400%). This latter feature is important because it permits the body to use more available fats for energy production, that is, more fat is extracted from normal blood to fuel exercise.
Changes in VO2max increase within a week of exposure to a constant aerobic training stimulus. After three weeks of exposure the stimulus no longer overloads the system resulting in the cessation of aerobic capacity development. It is good practice to increase the overload factor in aerobic endurance training every 7 to 14 days to allow an athlete to progress at an optimal rate of adaptation.
When training for aerobic endurance ceases, there usually is a rapid fall in capacity within the first two weeks and then the decline is more gradual.
In athletes who have an extensive history of aerobic training (a considerable number of years) the mitochondrial regression occurs at a much slower rate than that which is demonstrated by individuals without a good training background.
Once an athlete's aerobic capacity has been developed fully for a specific sport, the adaptation level can be maintained with less training. As long as the intensity of the training stimuli remain the same as that which existed in the last stage of change training, the number of aerobic training sessions can be reduced to one third of the change-training amount without any diminution in aerobic capacity.
Swimmers performed significantly faster in the late afternoon than early in the morning. Evening practice swims should be expected to be faster than those at a morning practice.
Distinctive circadian rhythms for pulse rate, rectal temperature,
and both power measures were exhibited. The general time for the peak
was after hr. The
between the highest and lowest values in the rhythm was 14% for mean
11% for peak power
AFTERNOON TRAINING IS BEST FOR AEROBIC ADAPTATION
Torii, J., Shinkai, S., Hino, S., Kurokawa, Y., Tomita, N., Hirose, M., Watanabe, Shuichiro, Watanabe, Seiichiro, & Watanabe, T. (1992). Effect of time of day on adaptive response to a 4-week aerobic exercise program. Journal of Sports Medicine and Physical Fitness, 31, 348-352.
Healthy men were assigned to groups that trained in the morning (N = 4; 9:00 to 9:30 AM), afternoon (N = 4; 3:00 to 3:30 PM), or evening (N = 4; 8:00 to 8:30 PM). Ss worked by pedaling a cycle ergometer for 30 minutes at 60% VO2max.
The following were found.
Implication. This study suggests that
aerobic training is most effective in the afternoon. Training effects
are less in morning or late evening practices. Performing at those
times is probably best designed for physiological maintenance rather
SOME SLEEP DISRUPTION IN NON-OVERTRAINED ATHLETES
DURING PEAK TRAINING
Taylor, S. R., Rogers, G. G., & Driver, H. S. (1997). Effects of training volume on sleep, psychological, and selected physiological profiles of elite female swimmers. Medicine and Science in Sports and Exercise, 29, 688-693.
Sleep and psychological changes in female swimmers (N = 7) were examined across a competitive swimming season. Full analyses were performed at season onset, peak training, and taper. A daily sleep diary was completed each day of the study.
Sleep onset latency, time awake after sleep onset, total sleep time, and rapid eye movement sleep times were similar at all training stages. Slow wave sleep formed a very high percentage of total sleep at onset (26%) and peak (31%) training but was significantly reduced during taper (16%). This supports the theory that restorative slow wave sleep is reduced with reduced physical demand. The amount of movement during sleep was significantly higher during peak training volumes suggesting some sleep disruption.
In contrast to several other studies reported on mood disturbance and swimming, in this investigation mood actually deteriorated as training volume decreased. One explanation for this contradictory finding was that these Ss were not overtrained.
Implication. The nature of sleep is affected by training stress with increased stress resulting in increased slow wave sleep and body movements. However, since Ss in this study were not overtrained it is possible that different disruptions could occur in overtrained Ss.
Training for as little as two days per week is enough to maintain
performance, provided that the exercise intensity is high (85-100% VO2max). Anaerobic threshold can be
during periods of reduced training by as few as one high intensity
session per week.
In the transition and basic preparatory phases, the anaerobic threshold (ANThreshold) should be trained to its highest level. Its development will directly effect the volume of all types of training that can be completed. It will also contribute to the quality of continuous training tasks that can be sustained (e.g., overdistance training of 2000 m or more) as well as enhance recovery.
The next emphasis in the basic preparatory phase should be to develop the aerobic capacity (VO2max) to its fullest. It will complete the stimulation of all the beneficial changes that are derived from aerobic training. It will also allow some proportion of the fast-twitch muscle fibers to be "converted" to oxidative functioning. For maximum aerobic performance (e.g., 800 and 1500 m events) this capacity needs to be developed fully.
The latter part of the basic preparatory phase should include an increase in the intensity of work. Lactate tolerance or peak lactate training develops the body's ability to use anaerobic energy sources and to tolerate high lactate levels. This capacity will govern the contribution to performances where energy production is a limiting factor (e.g., 200 m butterfly). Individuals can improve this ability to tolerate the pain of lactic acidosis but only up to a point. There comes a time when the acidity is so extreme that it seriously disrupts an individual's capacity to perform. At the most extreme point (the ceiling level), the body will shut down and the athlete will lapse into unconsciousness. It is wise not to push oneself to that ultimate state because of health risks. In sports it is of no advantage to get to that level because skills and performance will be so poor that acceptable conduct will not occur. Thus, most competitive sports with their emphasis on skill, speed, and power do not foster or encourage excessive levels of lactate tolerance. Even if an athlete could tolerate high levels of lactic acid it will not be beneficial for achieving high levels of performance. That is particularly so in the skill dominated sport of swimming. Lactate tolerance training should only be performed at race-specific velocities for each of the competitive strokes and their events. It makes little sense to talk of a general capacity of lactate tolerance when the sport of swimming contains very specific events each with their own levels of demand for use of anaerobic energy.
The final capacity that should be stimulated in the hierarchy of
conditioning is anaerobic power. Anaerobic power training refers to
the capacity of the body to generate as much energy as possible per
time. It traditionally is discussed in terms of anaerobic energy
although an aerobic component is always involved. Anaerobic power is
particularly important for 50 and 100 m events. A large portion of this
capacity is not physiological but rather involves a neural
refinement of existing physical structures developed by previous
TRAINING LEVELS FOR SWIMMERSSharp, R. L. (1993). Prescribing and evaluating interval training sets in swimming: a proposed model. Journal of Swimming Research, 9, 36-40.
Sprint ability. This is one's maximum velocity and is a function of muscle fiber type, level of creatine phosphate in the muscles, activity of creatine kinase in muscles, maximum muscle power, and neuromuscular recruitment patterns. A swimmer has to develop the skill of reaching maximum velocity as soon as possible in a race, to maintain maximum velocity for as long as possible, and develop the ability to call upon sprint ability in the middle and at the end of longer (>30 sec) races.
Lactate Tolerance. When muscles contract they produce lactic acid because of incomplete oxidation of carbohydrate used as fuel. After its formation, it immediately splits to form lactate and hydrogen ions (H+). The H+ ions alter the acidity of the blood, lowering its pH value depending upon their concentration. This reaction is why the terms lactic acid and lactate often are used interchangeably. Thus, the pH of blood is a measure of the amount of H+ in the body. When the H+ ions are allowed to accumulate, the pH in the muscles falls, that is, the environment in the muscles increases in acidity. A normal resting measure of pH is 7.0 whereas in very strenuous work that predominantly uses anaerobic energy sources the level can drop to a value of 6.3. As the acidity level changes (the pH level is lowered), the muscles become weaker, often tighter, and contractile force is reduced. As blood and muscle acidity increase, so does the feeling of fatigue.
At low intensities of exercise, for example, ANThreshold training, the rate at which lactic acid is produced is balanced by the rate at which it can be removed from muscle and blood. However, as a swimmer speeds up, for example, at aerobic capacity speeds and faster, the use of carbohydrate as fuel is greatly increased, and the production of lactate is greater than the ability of the lactate-removal mechanisms. Thus, after a certain intensity of work, that is, swimming at a particular speed for a minimum duration, lactate accumulates.
Resting or normal activity levels do not tax the capacity to remove lactate. Exercise can increase the production of lactate from 3-5 times above the resting level without any appreciable change in a muscle's pH. This is because the body has buffers which combine with the H+ ions and remove them from bodily fluids. The greater the amount of buffer capacity, the greater can be the intensity of work before H+ ions accumulate and lower the blood pH. The buffering capacity of muscle determines its ability to tolerate lactate before the pH is altered noticeably. Fast twitch muscle fibers have a greater buffer capacity than slow twitch fibers. Buffer capacity can be increased through training. It is very helpful to assess a swimmer's ability to tolerate lactate accumulation because it will indicate the changes derived from training designed to increase the amount of anaerobic work that can be sustained.
Aerobic power. This is a person's maximum ability to use oxygen. It is the upper limit or ceiling for aerobic endurance. Endurance athletes have a high capacity but it does not differentiate between them. It is a requirement for achieving an elite status but is not related to performance among an elite homogeneous group.
Aerobic endurance. This is a measure of an athlete's ability to perform prolonged, continuous exercise and depends upon physiological, biomechanical, nutritional, and psychological factors. The best measure currently available is the lactate or anaerobic threshold. It determines the maximum speed a swimmer can sustain without experiencing progressive accumulation of lactate in the blood. However, there are no pool races that use this capacity. Thus, its contribution to race quality is questionable. Rather, it serves as the basis for a general conditioned state.Two reasons justify aerobic endurance training. It contributes to accelerated recovery from fatiguing work and it extends one's ability to tolerate the demands of lactate tolerance, aerobic power, and speed training. This form of training may be the easiest and most efficient way of improving a swimmer's stroking economy which in turn, means that a swimmer can swim at faster speeds before reaching lactate threshold
Response systems are also dependent upon the mechanical function doing the work. For effective training at least the appropriate biomechanical actions (technique and its constituent neuromuscular pathways) must be maintained and repeated while the appropriate energy system is fatigued. Irrespective of the development level of an athlete's technique, when in a non-fatigued state, an athlete usually works as efficiently as possible, even though the technique might include some "errors." With the onset of fatigue caused by a training stimulus, muscle fiber and then muscle recruitment occurs, eventually resulting in a degradation of movement efficiency no matter what the standard of technique that originally existed. In the very early stages of fatigue, a loss of efficiency can be stalled by the athlete consciously striving to maintain essential technique elements, a compensatory activity that lasts only for a short time. Physical fatigue gradually becomes more general and reduces movement efficiency. Consequently, it is not worthwhile to persist with excessive fatigue that causes technical inefficiency when attempting to get the optimum benefit from a practice activity.
Once the activity's biomechanics are degraded, further
physiological overload is not warranted because the body will be
learning to energize an inappropriate and, very likely,
counterproductive action. Thus, for specific training to be beneficial
it has to include both the biomechanics and energizing system of the
intended competitive performance.
MUSIC AND RPE
Pujol, T. J., Pujol, K. J., & Creamer, D. R. (1996). Impact of music on rating of perceived exertion during leg ergometry. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 420.
Self-selected music-paced exercise responses were compared to metronome-paced exercise. Ss were required to perform two 10-minute paced bouts of leg ergometry. The music used was that preferred by each S.
The music condition yielded lower ratings of perceived exertion.
Implication. Allowing exercisers to
perform while listening to music they have selected is likely to
increase the work volume performed during an exercise bout.
MUSIC AND RPE DURING AEROBIC EXERCISE
Raynor, D. A., & Raynor, J. O. (1996). Effects of auditory stimuli on perceived exertion and behavior during aerobic exercise. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 427.
The influence of auditory stimuli (e.g., music, auditory book, negative sound effects) and a white noise control on ratings of perceived exertion (RPE) during an acute bout of aerobic exercise was evaluated.
No significant differences in heart rate were found between conditions. RPE in the music condition was significantly lower than the control (white noise) condition. The psychological component of the music condition affected the RPE as well as the physiological demands of the task.
Implication. Psychological variables can cause RPE to change even though the task remains constant.
Maximal metabolic responses of competitive runners (N = 9) were compared for treadmill running, deep water running, and shallow water running.
Results. Treadmill running elicited higher VO2max and HRmax than either water test. VO2max was higher for shallow water than deep water running. Respiratory exchange ratio and lactic acid measures did not differ between the conditions.
Implication. Even though trained runners "ran" in three
different milieus, the metabolic costs and response patterns were
different. It would appear that there would be no specific benefit to
running in any of these conditions because of the incorrect energy
supply mechanisms for pure running. The actual benefits of such
training, other than in the most basic/general phases of training have
to be questioned.
SOME SUPPORT FOR CROSS-TRAINING
Bushman, B. A., Flynn, M. G., Andres, F. F., Lambert, C. P., Taylor, M. S., & Braun, W. A. (1997). Effect of 4 wk of deep water run training on running performance. Medicine and Science in Sports and Exercise, 29, 694-699.
Whether trained competitive runners could maintain on-land-running performance using 4 weeks of deep water run training instead of on-land training was investigated.
Well-trained competitive runners (M = 10; F = 1), trained exclusively using deep water run training for 4 wk. Ss trained 5-6 days per week for a total of 20-24 sessions. Instruction and practice sessions were conducted prior to the training period. Before and after the deep water run training, Ss completed a 5-km race on the treadmill using a computer based system, a submaximal run at the same absolute workload to assess running economy, and a combined lactate threshold and maximal oxygen consumption test.
No significant differences were found for 5 km run time, submaximal oxygen consumption, lactate threshold running velocity, or maximal oxygen consumption. Also no differences were found among Global Mood State pre-training, each week during training, and post-training.
Competitive distance runners maintained treadmill running performance using 4 weeks of deep water run training as a replacement for on-land training.
It is possible that the treadmill running task was not reflective of the specific qualities of ground running and therefore is a measure that is independent of the specific nature of ground running. If this is the case, then it does not reflect the idiosyncrasies of specific running and should not be expected to change as a result of other unrelated (deep-water) training.
Implication. Well-trained runners were able to maintain trained running performances by running in deep water. This would support "cross-training" of this nature but needs to be replicated before it is accepted as supporting cross-training in light of the overwhelming evidence that supports the principle of specificity. The nature of measures of training in this study may not have produced a valid evaluation of the hypothesis that was tendered.
DEEP WATER AND TREADMILL RUNNING; SIMILAR IN SOME
MEASURES AND DIFFERENT IN OTHERS
DeMaere, J., & Ruby, B. C.. (1997). Effects of deep water and treadmill running on oxygen uptake and energy expenditure in seasonally trained cross country runners. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1264. [Published at greater length as DeMaere, J. M., & Ruby, B. C. (1997). Effects of deep water and treadmill running on oxygen uptake and energy expenditure in seasonally trained cross country runners. Journal of Sports Medicine and Physical Fitness, 37, 175-181.]
Deep water and treadmill running at 60 and 80% VO2max were compared on a number of physiological variables.
VO2 and energy expenditure were similar in both exercise modalities indicating the overall active muscle mass was quite similar. However, other variables were significantly different. Ventilation and respiratory exchange ratio were higher in deep water running suggesting that the pattern of muscular recruitment was altered particularly at the higher level of effort.
Implication. Although deep water running is a popular training modality for rehabilitation and appears to elicit similar rates of energy expenditure to that of treadmill running, the concepts of training specificity have to be considered when training for running on land. Deep water running does not appear to have any added values to that which could be achieved by solely indulging in land training.Return to Table of Contents for this
SPECIFICITY OF AEROBIC TRAINING
Ray, C. A., Cureton, K. J., & Ouzts, H. G. (1990). Postural specificity of cardiovascular adaptations to exercise training. Journal of Applied Physiology, 69, 2202-2208.
This investigation was designed to answer two questions:
Sedentary men (ages 18-33) were divided into two groups (N = 8). Training consisted of high-intensity interval and prolonged continuous cycling in supine or upright postures 4 days/wk, 40 min/day, for 8 wk. Seven other men served as non-exercising controls. Both specifically trained groups were tested in the two postures.
In the supine group, VO2max increased 22.9% in the supine position and 16.1% in the upright position. In the upright group, VO2max increased 6.0% in the supine posture and 14.6% in the upright position. No changes occurred in control Ss.
When performing submaximal work in the supine posture, the supine-trained group increased end-diastolic volume (21%), stroke volume (22%), and decreased heart rate, blood pressure, and systematic vascular resistance. By contrast, the upright-trained group only displayed a significant decrease in blood pressure.
When performing submaximal work in the upright posture, a significant decrease in blood pressure occurred in the supine group, but significant increases in end-diastolic volume (17%) and stroke volume (18%) and decreases in blood pressure and systematic vascular resistance were displayed by the upright-trained group.
Blood volume increased significantly in the upright-trained group but not in the supine-trained group.
No changes in volume of myocardial contractility, ejection fraction, and systolic blood pressure-to-end systolic volume ratio were observed in either posture in either trained group. No significant metabolic changes occurred in the control group.
These results indicate that changes due to training were posture specific and did not generalize (transfer or cross-train) to the other posture. Neither form of posture training elicited cardiovascular adaptations at rest or during exercise in the posture not used for training. The magnitude of cardiovascular changes to training in the two groups was similar.
Implication. The extreme specificity of cardiovascular training was exhibited in this study. Only the postural position differed between the two groups with the nature of the work and activity being controlled and similar. That one variable alone was sufficient to cause specific and non-generalized training effects.
It is unreasonable to assert that cardiovascular
training effects in one activity in one posture (e.g., upright running)
would not transfer to another activity in a different posture (e.g.,
supine swimming). These results indicate that advocating
"cross-training" effects between different activities and/or postures
SPECIFICITY OF THE TAPER - RUSSIAN MARATHONERS
Velikorodnih, Y., Kozmin, R., Konovalov, V., & Nechaev, V.
(1986). The marathon (precompetitive preparation). Soviet Sport
Review, 22(3), 125-128.
When training during the last four weekly microcycles it is best to stabilize the achievements of previous training. No attempt should be made to develop any last-minute gains (this was done by many athletes in the study).
The most common mistake was trying to raise the speed potential with the use of 400 - 1,000 m repetitions at speeds significantly higher than would be performed in a marathon race. All athletes who tried this speed work failed. It is felt it disrupted more than enhanced established performance capacity.The successful athletes trained at the speeds that would be experienced in the race. Since a marathon has a variety of speeds, depending upon conditions, stage of race, terrain, and climate (wind and heat), one should train over that range rather than only at the single predicted average time. For marathons it was suggested to develop the average predicted speed and vary training between -8 - +10 sec around the mean in the first microcycle but gradually reduce the range to -3 - +5 sec by the last microcycle.
For a marathon, the authors suggest that the
range of training
intensities should be restricted over the last four weeks with the
volume of work decreasing weekly. This way the athlete will be primed
for a particular range of performance capabilities but will also be
EXCESSIVE ANAEROBIC TRAINING CAUSES OVERTRAINING
Urhausen, A., Gabriel, H., & Kindermann, W. (1995). Blood hormones as markers of training stress and overtraining. Sports Medicine, 20, 251-276.
Anaerobic lactic exercise forms are one important trigger
mechanism for inducing overtraining. The frequency of competitions or
training sessions with higher anaerobic lactic demands, should be
carefully limited in order to prevent overtraining syndrome.
PSYCHOLOGICAL VARIABLES ARE BETTER DETECTORS OF OVERTRAINING THAN PHYSIOLOGICAL VARIABLES
Theriault, D., Richard, D., Labrie, A., & Theriault, G. (1997). Physiological and psychological variables in swimmers during a competitive season in relation to the overtraining syndrome. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1237.
During a competitive swimming season a group of 22 swimmers was followed in order to assess levels of psychological stress, clinical fatigue, and potential physiological markers of stress and fatigue. Swimmers completed a battery of tests in order to evaluate training status at four stages of a training season (post-training camp, taper, high volume-high intensity, and post competition).
No correlations were found between psychological and clinical variables and the different physiological variables. Physiological variables were not altered when moderate elevations of stress and fatigue were detected consistently by psychological and clinical instruments. Measuring physiological variables does not seem useful in the detection of the overtraining syndrome when moderately high levels of stress and fatigue are encountered in the yearly monitoring of elite swimmers.
Implication. Psychological variables are associated more with the onset of and moderate levels of overtraining than are physiological variables. When monitoring training responses, coaches would be well advised to monitor psychological variables rather than physiological variables. Physiological variables are relatively unreliable in the detection of overtraining symptoms and eventually the overtrained state. Using physiological measures is not warranted if monitoring the stress of training is the purpose of testing.
MONITORING OVERTRAINING - ANOTHER ATTEMPT
Hill, M. R., Motl, R. W., Estle, J., & Gaskill, S. (1997). Validity of the stamina index test for monitoring elite athletes. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 46.
The effectiveness of the Stamina Index Test (SIT) as a monitoring tool of morning heart rates in elite level Nordic and biathlon skiers during a winter of racing was assessed.
Skiers (M = 2; F = 6) performed the SIT every morning for six months. SIT involves using a heart-rate monitor to record resting (HR1), elevated after 30 knee-bends (HR2), and recovery heart rates (HR3) and is calculated as (HR1+HR2+HR3-200)/20. Variables assessed were fluid intake prior to SIT, hours of sleep, internal variables, training hours, and training intensity. Cannonical correlation analyses related the variables. Two significant correlations were revealed.
Implication. Sleep is a significant value for producing better physical function and mental states. This should be a major factor involved in recovery periods or taper periods prior to important competitions. Elevated heart rates also indicate poor status of feeling and health although the degree of association is relatively low.
The provision of opportunities to obtain adequate sleep is a factor that must be considered in the training life of an elite athlete.
OVERREACHING IS LIKELY TO BE CAUSED BY PERIPHERAL
Hedelin, R., Kentta, G., Wiklund, U., Bjerle, P, & Henriksson-Larsen, K. (2000). Short-term overtraining: Effects on performance, circulatory responses, and heart rate variability. Medicine and Science in Sports and Exercise, 32, 1480-1484.
Elite athletes (canoeists; N = 9) volunteered for this training study. They participated in a 6-day training camp where the training load was approximately 50% greater than normal. Activities included endurance cross-country skiing (65%), strength training (10%), and high-intensity/anaerobic training (25%).
The athletes' performance and physiological markers declined over the short camp-period. Run time to exhaustion worsened, and heart rates at all workloads, VO2max, and Lamax decreased significantly. Plasma volume increased. No changes in high or low frequency heart rate variability were observed. The pattern of responses suggested that alterations were peripherally mediated rather than being centrally determined.
Implication. Fatigue from excessive training loads (overreaching) is likely to be peripheral in nature rather than caused by central circulatory factors.
Costill, D. L., & King, D. S. (1983). Workout evaluation. Swimming Technique, August-October, 24-27.
Costill and King directly commented on the value of "hell-week" programming where athletes are subjected to repeated days of intense and large volume swimming. Those experiences do not produce training effects because:
Implication.The practice of subjecting athletes to excessive
amounts of training as a method for developing "character" or locating
the "mentally-tough" athletes in a squad is irresponsible and could be
construed as physical abuse. There is enough evidence to support the
contention that "hell-week" forms of training are sufficiently
threatening to the well-being of athletes that litigation asserting
negligence on the part of a coach demanding participation in such an
experience is a distinct possibility.
NEGATIVE AND POSITIVE SELF-TALK AND TENNIS PERFORMANCE
Van Raalte, J. L., Brewer, B. W., Rivera, P. M., & Petitpas, A. J. (1994). The relationship between observable self-talk and competitive junior tennis players' match performances. Journal of Sport and Exercise Psychology, 16, 400-415.
The effect of self-talk on the performance of 24 junior tennis players (mean age 15.4 yr) during tournament matches was examined. It was found that negative self-talk was associated with losing and that players who reported believing in the utility of positive self-talk won more points than players who did not.
The results suggest that the type of self-talk engaged in by athletes influences competitive outcomes.
Implication. It is important for athletes to know why and how to engage in positive self-talk as part of their competition conduct.
MATURE ROWERS PERFORM BETTER WHEN THINKING POSITIVELY
Rushall, B. S. (1990). An assessment of the effects of psychological support services on college varsity male rowers. Research report for US Rowing, Indianapolis, IN.
Members of a prominent intercollegiate varsity men's rowing program were instructed to develop and use positive self-talk. In a 6 min ergometer test trial, Ss (N = 8) were directed to use normal test-trial thinking for a one minute interval and the prepared positive thoughts for another minute. These minutes of thought concentration were alternated throughout the trial.
Seven Ss' times improved in the positive thinking condition by an average of -1.17%, while one was marginally worse. Ss were not aware of any performance difference between the two thought conditions until told by the experimenter.
Implication. Mature rowers were able to improve serious training performances by concentrating on prepared positive thoughts. The type of thinking developed "naturally" at practice, does not appear to be conducive to the best quality of training response. Instruction about how to think positively is a simple, easy coaching procedure, and is embraced by mature varsity rowers.
POSITIVE VERSUS NEGATIVE THINKING
Taylor, D. E. M. (1979). Human endurance - mind or muscle? British Journal of Sports Medicine, 12, 179-184.
Subjects were 5 male officer cadets, aged 19-23 years exposed to a variety of "atmospheres" while undergoing particularly challenging and enduring tasks.
Implication. Do not add stress in competitions - the disruption has a physiological cost. Do not change the perception of external pressures or the task once a contest begins.
Implication. Self-efficacy is increased if there is a perceived probability of positive outcomes.
Implication. Performance threats during an activity are stressful and reduce performance potential and the quality of the performance.
If a person believes he/she will not be successful or survive, then a psychological stress-spiral is induced resulting in an inappropriate cardiovascular response with tachycardia and hypertension in excess of cardiac output changes stimulated by the exercise. It is caused by too much adrenaline rather than too little. When a person believes he/she will be successful, no change in cardiovascular response will occur while performance will be improved by increased power and sustained effort.
If an athlete views a competitive situation as being stressful or negative, then physiological functioning will be less efficient than when it is viewed in a positive light.
Halvari, H. (1983). Relationships between motive to achieve success, motive to avoid failure, physical performance, and sport performance in wrestling. Scandinavian Journal of Sports Science, 5, 64-72.
Norwegian wrestlers, 14-17 years old, of varying abilities [good for correlations] were tested (N = 26). Nygard and Gjesme's Achievement Motives Scale was used. Statistics determined were Pearson product-moment correlations and t tests.
When successful athletes were compared to unsuccessful athletes it was found that:
Implication. The greater the amount of positiveness and the
less the negativeness in an athlete's reasons for participating in
sport, the better. Sporting success is correlated with high levels of
positiveness and few perceptions of negative features.
SELF-CONFIDENCE AND PERFORMANCE
Mahoney, M. J., & Avener, M. (1977). Psychology of the elite athlete: An exploratory study. Cognitive Therapy and Research, 1, 135-141.
Finalists in the 1976 US Men's Olympic Team gymnastic trials served as Ss. Those who reported experiencing occasional doubts about their abilities tended to do poorly during the qualifying meet. Among the 12 finalists, actual performance was moderately correlated (r = .57) with pre-meet self-confidence [possibly self-efficacy].
Implication. Predicting, and possibly justifying, that an
athlete will do well in an impending competition is one of several
major determinants of competition success. Such beliefs should not be
idle, but firmly established in facts and in particular, improved
training performances in close proximity to the competition.
PRECOMPETITION NEGATIVE THOUGHT EFFECTS
Dalton, J. E., Maier, R. A., & Posavac, E. J. (1977). A self-fulfilling prophecy in a competitive psychomotor task. Journal of Research in Personality, 11, 487-495.
Individuals who believed that the probability of success in performing a task was low, performed at a significantly lower level than those who perceived they had an advantage (an increased probability of success).
This gave rise to the phenomenon of the self-fulfilling prophecy. Whether or not failure was likely, those who believed they would fail facilitated that outcome, even though success could have been achieved.
Implication. In the days leading up to an important contest, thoughts should be controlled and structured. Activities such as role-playing successful aspects of performance, publicly justifying why one will do well, and positive performance enhancement imagery should be considered in precompetition strategies.
PRECOMPETITION STATEMENTS DEVELOP ASSERTIVENESS
Schwartz, R., & Gottman, J. (1974). A task analysis approach to clinical problems: A study of assertive behavior. Unpublished manuscript, Indiana University, Bloomington, IN.
In high-assertive Ss there was a marked excess of positive over negative self-statements and usually little doubt about the appropriateness of actions. In contrast, low-assertive Ss had equal positive and negative self-statements which appeared to compete against each and thus, interfered with personal behavior.
Implication. Examples of purely positive statements are:
"I will perform my best," "I will set the tempo of the game," "She had better watch out as I am ready for this match."
Examples of negative or doubting statements that reduce assertiveness are:
"I hope I can put on a good show against him," "If I could just score some points," "I pray that I will perform well."
Teaching athletes to perform positive/assertive statements and using them frequently in self-talk prior to competitions would contribute to desirable forms of event preparation.
Effect of the intensity of training on
catecholamine responses to supramaximal exercise in
Jacob C, Zouhal H, Prioux J, Gratas-Delamarche A, Bentue-Ferrer D, Delamarche P.
Laboratoire de Physiologie et de Biomecanique de l'Exercice Musculaire, UFR-APS, Universite de Rennes II, Av. Charles Tillon, CS 24414, 35044 Rennes Cedex, France. firstname.lastname@example.org
In this study we investigated whether plasma catecholamine responses to the Wingate test are affected by the intensity of training in endurance-trained subjects. To do this we compared plasma adrenaline (A) and noradrenaline (NA) concentrations in response to a Wingate test in three different groups: specialist middle-distance runners (MDR) in 800-m and 1,500-m races, specialist long-distance runners (LDR) 5,000-m and 10,000-m races, and untrained subjects (UT). The maximal power ( W(max)) and the mean power ( W) were determined from the Wingate test. Blood lactate (La), plasma A and NA concentrations were analysed at rest (La(0), A(0) and NA(0)), immediately at the end of the exercise (A(max )and NA(max)) and after 5 min recovery (La(max), A(5) and NA(5)). The ratio A(max)/NA(max )was considered as an index of the adrenal medulla responsiveness to the sympathetic nervous activity. At the end of the test, W(max) and W were similar in the three groups but La(max) was significantly greater in MDR compared to LDR and UT [15.2 (2.2) mmol l(-1), 11.7 (3.1) mmol l(-1), 11.6 (1.6) mmol l(-1), respectively, for MDR, LDR and UT; mean (SD)]. Concerning the plasma catecholamine concentrations in response to exercise, MDR and LDR A(max) values [3.73 (1.53) nmol l(-1), 3.47 (0.74) nmol l(-1), respectively, for MDR and LDR] were significantly greater than those of UT [1.48 (0.32) nmol l(-1)] who also exhibited the lowest NA(max) values [11.09 (6.58) nmol l(-1)] compared to MDR and LDR [20.43 (3.51) nmol l(-1); 15.85 (4.88) nmol l(-1), respectively, for MDR and LDR]. However, no significant differences were observed between the two trained groups either for A(max) or NA(max.) These results suggest that long-term endurance training can enhance plasma catecholamine concentrations in response to supramaximal exercise. However, as there were no significant differences between MDR and LDR A(max) and NA(max) values, the effect of the intensity of training remains to be clarified.
Jacobs, I. (1983). Blood lactate
and the evaluation of endurance fitness. SPORTS, W-2, 6
A German study (Hollman, Rost, Liesen, Dufaux, Heck, & Mader, 1981) showed that endurance training at a running speed which elicited a blood lactic acid concentration of 4 mM caused a greater improvement in endurance performance than did training at a higher intensity which elicited 7-9 mM. This finding does not support the old axiom that the "harder" one trains, the greater will be the improvement. There are numerous studies which suggest that exercise corresponding to a 4 mM level of lactic acid accumulation, or close to it, is optimal in terms of the stimulus for aerobic adaptation in the muscle cell, and that this intensity reflects the highest exercise intensity at which most of the energy for muscular contraction is still derived from aerobic metabolism.
LACTATE TESTING AND USES IN SWIMMING
Troup, J. P. (Ed.). (1990). Selection of effective training
categories. In International Center for Aquatic Research annual:
Studies by the International Center for Aquatic Research 1989-90.
Colorado Springs, CO: United States Swimming Press.
Lactate testing is a good indicator of how one responds to an overload but is not good for prescribing training paces specific to work categories. This is because lactate removal rates vary between athletes and do not depend on training intensities. Lactate values must be used with caution and testing should be limited to simply describing how muscles adapt to different workloads and whether an overall training adaptation is taking place.
Lactate accumulation appears to be duration dependent because
some longer races (200 and 400 m) produce more lactate. The need for a
strong buffer capacity is highest for the 200 m event. This suggests
that lactate tolerance training is very important for that distance.
LACTATES AND ENDURANCE PERFORMANCE
Rusko, H. (1986). Analysis of physiological response to training and competition among Finnish endurance athletes. Athletic Performance Review, 1(10), 1-2. (Abstract)
Terminal lactates were taken on Finnish cross-country skiers at the end of championship events (males 15 km and females 5 km). The following were found for the males:
The following were found for the females:
THE LACTATE CONCEPT
Gladden, L. B., Spriet, L. L., Donovan, C. M., Bonen, A., & Brooks, G. A. (1997). The role of skeletal muscle in lactate exchange during exercise. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 424.
"Lactate is not simply a dead-end metabolite which is produced in skeletal muscle in response to hypoxia. Instead, lactate is produced by many tissues under many different conditions, transported throughout the body, and taken up and metabolized by many tissues. This 'lactate shuttle' necessarily involves lactate metabolism and the membrane transport of lactate, especially in skeletal muscle. Historically, skeletal muscle was viewed as a producer of lactate; however, skeletal muscle (both at rest and during exercise) is now known as not only a major source of lactate, but also as the most important consumer of lactate." (p. S74)
Stephen Seiler (http://www.sportsci.org/news/news9707/seiler.htm) commented on this symposium. Some of his remarks, which summarize the content of the presentations and are appropriate for coaching science, are listed below.
THE ORIGIN OF LACTATE IN EXERCISE
Brooks, G. A. (1991). Current concepts in lactate exchange. Medicine and Science in Sports and Exercise, 23, 895-906.
Coaches and many sport scientists consider lactate as a representation of oxygen-limited metabolism (anaerobic glycolysis) during exercise. Recent research has shown this to be too simplistic. The formation, exchange, and utilization of lactic acid (lactate) represents an important means of distributing carbohydrate (CHO) energy sources after a carbohydrate meal and during sustained physical exercise. Lactate is now viewed as being a beneficial intermediary metabolite between CHO storage forms (glucose and glycogen) and metabolic end products (CO2 and H2O). The advantage of lactate as an intermediary is that it exchanges rapidly between tissue compartments.
Skeletal muscle, once considered to be the major site of lactate formation, in some circumstances is responsible for significant net lactate removal from the blood. The liver, once thought to be a primary site of lactate removal through its role in the Cori cycle, can contribute in a major way to a rise in arterial lactate, particularly at the onset of strenuous exercise. During exercise, lactate is the predominant fuel for the heart. Other tissues and organs (e.g., skin, intestines) are also involved in blood lactate kinematics during exercise.
Lactate can be formed in fully aerobic tissue, such as the heart, and used within those same tissues.
The finding that lactate can be formed in and released from diverse tissues such as skeletal muscle, liver, and skin under resting conditions of CHO loading and epinephrine stimulation, counters the long-held belief that lactate is formed as the result of oxygen-limited metabolism. There is a lack of evidence that a limitation of oxygen supply causes lactate production, but much evidence to show that it is formed in circumstances of adequate oxygen supply. Factors of substrate supply and mass action are responsible for lactate formation.
Contracting skeletal muscle is not the only contributor to the rise in arterial lactate during exercise. Emotional stimulation, which leads to the release of epinephrine, causes a notable increase in arterial lactate (release from muscles). At high work rates, epinephrine infusion leads to a pattern of accumulation suggesting threshold level.
Arterial blood lactate levels are highly correlated with epinephrine levels. The blood lactate inflection point in graded exercise coincides with the epinephrine inflection point. Moderate exercise intensities result in almost no increase in catecholamine levels (epinephrine and norepinephrine). But beyond 50-70% VO2max, catecholamine levels rise disproportionately. Thus, lactate accumulation largely results from the level of effort and associated hormonal release not oxygen deprivation.
Lactate production has been found in fully oxygenated muscles. Thus, muscle lactate level may not always be a suitable indicator of lack of oxygen (anaerobic work).
Net lactate output from contracting muscle is related to the intensity of stimulation. During prolonged steady-state conditions, contracting muscles can take up lactate on a net basis, especially in the arterial lactate concentration is elevated. Even under conditions of reduced oxygen supply, lactate is increased even if muscle oxygen consumption (VO2) is maintained. That is why lactate is a poor indicator of a lack of oxygen.
During continuous exercise at submaximal levels, lactate rises at first and then declines towards resting levels. When lactate is maintained at an elevated level, it cannot be explained on the basis of net lactate release from the exercising limbs. Exercising muscles can contribute to circulating lactate but active muscle is not the sole contributor to blood lactate concentrations. Exercising skeletal muscle is capable of simultaneously producing and removing lactate. Thus, lactate concentrations cannot be used to quantify lactate production.
The formation of lactate from endogenous (glycogen) as well as exogenous (dietary) carbohydrates represents a major means by which intermediary metabolism in diverse tissues and cells can be coordinated. The concept of lactate being the by-product of muscle activity under oxygen deprivation is inadequate and largely untrue.
LACTATE PRODUCTION IN MUSCLES
Stanley, W. C., Gertz, E. W., Wisneski, J. A., Neese, R. A., Morris, D. L., & Brooks, G. A. (1986). Lactate extraction during net lactate release in legs of humans during exercise. Journal of Applied Physiology, 60, 1116-1120.
During exercise, working muscles extract a significant amount of lactate during net lactate release. Working muscles are also a significant source of lactate removal. Since not all fibers in a muscle are elicited to work excessively during exercise, and therefore do not produce lactate, one could hypothesize that those non-lactate-producing fibers are one site of lactate extraction. Other muscle groups that perform work during exercise but do not contribute markedly to power or movement production, extract more lactate than they produce.
Implication. Lactate produced in exercise is extracted by working and movement-supporting muscles.
THE LACTATE SHUTTLE
Brooks, G. A. (1986). Lactate production under fully aerobic conditions: The lactate shuttle duing rest and exercise. Federation Proceedings, 45, 2924-2929.
Oxygen insufficiency and other factors increase the rate of lactate production. Significant quantities of lactate are produced under postabsorptive as well as postprandial conditions in resting individuals.
During sustained submaximal (in terms of VO2max) exercise, the rates of lactate production (Ri) and oxidation (Rox) are greatly elevated compared to rest. However, lactate production and oxidation increase relatively less than oxygen consumption during moderate-intensity exercise. Because the lactate production index (RiI = Ri / VO2) decreases during submaximal moderate-intensity exercise compared to rest, skeletal muscle and other sites of lactate production are effectively oxygenated.
Lactate production occurs despite an apparent abundance of oxygen. Similarly, glucose catabolism in the human brain results in lactate production. The formation of lactate under fully aerobic conditions of rest and exercise represents an important mechanism by which different tissues share a carbon source (lactate) for oxidation and other processes such as gluconeogenesis. That mechanism has been termed the "lactate shuttle."
RELATIONSHIP BETWEEN HEART RATE AND LACTIC ACID http://www-rohan.sdsu.edu/dept/coachsci/csa/vol15/howat.htm
Howat, R. C., & Robson, M. W. (June, 1992). Heartache or heartbreak. The Swimming Times, 35-37.
Swimmers were instructed to perform aerobic swims at threshold. They were asked to count their heart rates after a particular swim. One minute after completion of the exercise a whole blood lactic acid analysis was conducted at poolside. Swimmers were divided in seniors and age groupers.
"Some extremely disturbing aspects of normal training became apparent. Irrespective of the expected wide variations of swimmers' estimates of their heart rates, the percentage whose bodies are gaining any benefit from training is at the most 33 per cent. This is similar to, and with age group swimmers greater than, the degree to which they are inadvertently overtraining. A similar proportion of time can be spent under-training." (p. 37)
"Whole blood lactate levels of around 3 mM equates to the anaerobic threshold for females (3.5 mM for males). . . . it is critical that, at threshold, pulse rate determined training is at least 10 beats per minute less than in males, if the same training effect is desired. Failure to recognize this important fact could result in major degrees of overtraining, especially in age group swimmers." (p. 37)
Using heart rates, such as those typically published to suggest a range within which a particular type of training effect will be achieved, to estimate work will roughly undertrain 33%, stimulate 33%, and overtrain 33% of swimmers in a squad for the purpose of achieving the same training effect.
When swimmers were instructed to train keeping their heart rates within a normal range for aerobic work prescription, the responses within the squad were anything but what was intended. A uniform training intensity based on usual heart rate estimates for aerobic stimulation does not result in a uniform training response, in fact, all manners of adaptation result within a squad. The following table shows that the variety of responses are similar for age-group and senior swimmers.
Seniors Percentage 8.3 33.3 33.3 25
Training nil no increase increase decrease
effect aerobically aerobically
Age Percentage 4.1 25 33.3 37.5
Training nil no increase increase decrease
effect aerobically aerobically
Lactate levels (mM) <1.5 1.5 - 2.4 2.5 - 3.4 >3.5
Implication. Using absolute heart rates as an estimate of
training intensity across a squad will train, undertrain, and overtrain
swimmers in roughly similar proportions, that is, only one in three
will respond as intended. If different rates are not used for women,
they will be grossly overtrained because a given heart rate needs to be
less than males to have an "equivalent" intensity. Using heart rate
"norms" to prescribe work intensities in swimming is more erroneous
than accurate for achieving particular types of physiological response.
HEART RATE AND LACTATE CONCENTRATIONS IN CROSS
Gibbons, T. P., & Watts, P. B. (1993). Heart rate and blood lactate concentration during on-snow training in college cross country skiers. Medicine and Science in Sports and Exercise, 25(5), Abstract 734.
Heart rate (HR) and blood lactate concentrations (BLC) are used to monitor training intensities in cross country skiers. It is assumed that HR-BLC relationships derived in the laboratory will hold for various training intensities in the field. Expert skiers (M = 5, F = 3) were laboratory tested to determine training intensities I, II, III, and IV. Using freestyle techniques, overdistance training (Levels I and II) and interval training (Levels III and IV) were performed with HR and BLC being monitored frequently throughout the training sessions.
HEART RATE NOT A GOOD VO2MAX INDICATOR
Emmett, J. D., & McClung, J. A. (1993). Heart rate as an indicator of oxygen uptake & cardiac function during two swimming modes. Medicine and Science in Sports and Exercise, 25(5), Supplement abstract 634.
Freestyle and tethered swimming measures were taken. Heart rate
was not a good discriminator of aerobic properties between the two
different forms of activity. HR is not a good indicator of swimming
performance in different forms of swimming.
HEART RATE VARIATION AND PERFORMANCE PARAMETERS
Richardson, R. S., Verestraete, D., Hochstein, A., Schultz, W., Johnson, S. C., Luetkemeser, M. J., & Stray-Gundersen, J. (1993). The role of hypervolemic and stroke volume in the heart rate and oxygen relationship following intense training. Medicine and Science in Sports and Exercise, 25(5), Supplement abstract 582.
The effect of acute exercise training on HR, oxygen consumption (VO2), cardiac output (CO), stroke volume (SV), plasma volume (PV), and running speed was studied in 14 male competitive runners. Two days of intense training (90-95% VO2max) followed baseline determinations.
HRmax was significantly reduced following the intense training (183 to 179 bpm). Both CO and VO2 were unaffected. PV increased by an average 6%. SV increased by an average of 4%. CO was maintained by SV.
Implication. The relationship between HR and VO2
is affected by training intensity. These changes in trained athletes
may be the result of a secondary PV expansion produced by intense
effort which raises SV and decreases HR.
PROBLEMS WITH HEART RATES AND SWIMMING
Ueda, T., & Kurokawa, T. (1995). Relationships between perceived exertion and physiological variables during swimming. International Journal of Sports Medicine, 16, 385-389.
"HR during swimming has some practical drawbacks that should be taken into consideration. For example, HR in water is 10 to 20 beats/min lower than in air . . . and is easily influenced by water temperature . . . Measuring HR by palpitate method is impractical. The palpitate method is also known to be rather inaccurate at HR over 130 beats/min" (p. 385).
Mental activity during
HEART RATE AND MENTAL-PHYSICAL ACTIVITY
Desharnais, R., Jobin, J. & Desgagnes, P. (1995). Interaction of physical and mental stresses on heart rate and effort sense during exercise. Medicine and Science in Sports and Exercise, 27(5), Supplement abstract 355.
Young adults (N = 128) exercised at 45, 60, or 75% of VO2max. During the task, Ss were instructed to perform mathematical tasks of different difficulty levels.
It was found that effort sense (rating of perceived effort) was only affected by physical stress. Mental activity altered HR depending upon the level of exercise exertion.
Implication. Novel mental tasks during high levels of exercise intensity increase the physical cost of a performance. In competitive settings, all the mental activity required for a performance should be practiced, familiar, and without distraction. The practice of coaches giving last-minute new instructions to athletes prior to performing, is likely to detrimentally affect performances if they are attended to.
Anaerobic threshold. Anaerobic threshold (ANThreshold) may be defined as the work load just below which steady-state exercise can continue for a prolonged time. It is used extensively for predicting aerobic performance. ANThreshold adaptation is stimulated by a certain amount of work. Extra work above that level will not result in any further adaptation and may even be harmful.
After periods of detraining, whether intentional or
unintentional (e.g., injury), aerobic fitness and the ANThreshold level
are quickly regained in athletes who perform training for most of the
AEROBIC TRAINING AT 4Mm PRODUCES AEROBIC ADAPTATIONS
Baltaci, G., & Ergun, N. (1997). Effect of endurance training on maximal aerobic power of competitive swimmers. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1260.
This study assessed the effect of endurance training on blood lactate concentration in college swimmers (M = 7; F = 7). Training intensity was centered on work that would yield 4 mM of steady-state blood lactate. Training lasted for six months.
The following were found.
Training that corresponded to 4mM of lactate concentration produced an improvement in anaerobic threshold as well as VO2max.
LACTATE THRESHOLD, VO2max, AND
VO2max and Lactate Threshold
VO2max and submaximal exercise capacity are limited by different mechanisms. VO2max appears to be related more to cardiovascular factors such as maximal cardiac output, whereas skeletal muscle metabolic factors including respiratory enzyme activity play more of a role in determining submaximal exercise capacity. This interpretation is supported by the fact that after training individuals work closer to their VO2max before attaining their lactate threshold. That means that cellular adaptations occurred more than changes in cardiovascular capacity. Oxidative enzymes increase as much as 100% through training while cardiac output increases to a much smaller extent.
Muscle respiratory enzyme activity is closely related to a person's LT when expressed in terms of absolute work rate. The correlations between mitochondrial respiratory enzyme activity and LT are generally better than those between enzyme activity and VO2max. "VO2max and LT are, within limits, determined by different physiological mechanisms, . . . LT is better related to the metabolic status of the peripheral musculature (i.e., skeletal muscle respiratory enzyme activity levels) while VO2max is more dependent upon cardiovascular factors relating to maximal cardiac output." (p. 108)
Lactate Threshold and Endurance Performance
Metabolic acidosis accompanying excessive muscle lactate production is generally believed to limit performance in short-term events lasting less than six minutes. On the other hand, lactate, or the accompanying decrease in muscle pH, is not believed to be a limiting factor for events lasting 10 to 120 minutes since blood lactate does not attain maximum levels.
"It is more likely that blood lactate level may provide an index of some other physiological signal which is actually the mechanism for limiting performance in prolonged steady-state competitive events." (p. 108)
While VO2max plays a role in determining the upper limit for aerobic expenditure in prolonged endurance events, LT measures provide a more precise prediction of endurance performance capacity. The preferred measures of LT come from long-duration continuous activity protocols rather than shorter, incremental protocols. The shorter protocols may be beneficial for studying ventilatory responses, but are tenuous when used to predict endurance performance capacities.
Thus, tests for LT, or whatever label is used, are better if they are of relatively longer rather than shorter duration, despite the greater time required for testing.
It is likely that "time available for testing" has
entered into testing protocol formulations. The quicker, cheaper, and
easier test is always appealing on efficiency grounds. The plethora of
testing procedures for both LT and VO2max has led to the
implicit inclusion of error into physiological measures. It is better
to do something correctly, than more expediently. LT is best measured
under extensive testing protocols and is the better index for
predicting endurance performance.
FURTHER ON ANAEROBIC THRESHOLD
Rushall Thoughts, 1988.
The anaerobic threshold is the state where the work of exercise can no longer be supported through aerobic energy supply alone. Above that state lactic acid begins to accumulate.
In an untrained state, the anaerobic threshold is a measure of the aerobic capacity of one's system. With training and consequent adaptation to exercise stress, the nature of the slow-twitch fibers changes. There is an increase in the capillarization within the muscle fiber bundles as well as the number of mitochondria in each fiber. That means that after training the amount of oxygen that can be used by the body is increased. Consequently, more work than in the untrained state can be performed before lactic acid starts to accumulate because of aerobic insufficiency. This results in one of the effects of aerobic training being an improvement in the anaerobic threshold.
However, the anaerobic threshold change that results from aerobic training is not only due to slow-twitch fiber adaptations. If the level of exercise strain is high enough some fast-twitch fibers will also adapt and become fast-twitch oxidative fibers. They will be recruited when the level of exercise approaches the anaerobic threshold. Thus, aerobic adaptation results in an anaerobic threshold shift because of principally slow-twitch fiber adaptations and, to a lesser extent, fast-twitch fiber adaptations.
This means that for maximum aerobic adaptation it is necessary to perform work of sufficient intensity to stimulate the use of fast-twitch fibers while almost the maximum aerobic capacity is being taxed. This is best achieved in interval work, or high-intensity fartlek work where the athlete periodically exceeds the existing anaerobic threshold in the one training session. Without the high intensity of work that requires the use of fast-twitch fibers, a maximum aerobically trained state and level of anaerobic threshold will not be attained.
For events that require both aerobic and anaerobic components
in performance it is best to perform the greatest amount of work
possible using both capacities at the pace of the intended performance.
Any slower pace will not stimulate the full capacity and any faster
pace will not produce sufficient volume of work to maximally adapt the
aerobic system. Thus, a central theme of much training for many sports
will be to perform training stimuli at such an intensity that
fast-twitch fibers will be recruited and "converted" to perform aerobic
COMPARISON OF LACTATE AND VENTILATORY THRESHOLDS
Wyatt, F. B., Tran, Z. V., Jackson, C. G., Brustad, R. J., & Banchero, N. (1996). Comparison of lactate and ventilatory threshold to maximal oxygen consumption: A meta-analysis. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 402.
Sixty-one studies were reviewed and subjected to a meta-analysis to determine associations between lactate (LT) and ventilatory (VT) inflection points and maximal oxygen consumption. The following were concluded.
It was concluded that LT measures can be considered for determining lactate inflection point.
Vmax AND Tmax
INTENSITIES PRESCRIBE GOOD TRAINING STIMULI FOR ENDURANCE ADAPTATION
Smith, T. P., McNaughton, L. R., & Marshall, K. J. (1999). Effects of 4-wk training using Vmax/Tmax on VO2max and performance in athletes. Medicine and Science in Sports and Exercise, 31, 892-896.
This study determined the effects on endurance of a 4-week individualized training program using Vmax (the speed at which an athlete performs when VO2max is elicited) as the exercise intensity, and using between 60 and 75% of a S's Tmax (time spent at Vmax) as the exercise duration. Male, middle-distance, trained Ss (N = 5) completed a 3000-m time trial, and three each of VO2max/Vmax and Tmax tests before training commenced. Ss then completed a 4-week training program on a treadmill and were then retested on the VO2max/Vmax and Tmax tests and the time trial.
Training produced significant increases in average, Tmax, and VO2max. A 3000-m time trial decreased significantly from a pretraining value of 616.6 s to a post-training value of 599.6 seconds.
This study showed that using between 60 and 75% of Tmax as an exercise duration and using Vmax as an exercise intensity can be valuable in the prescription of exercise programs for athletes.
Implication. Endurance performances improve when Vmax is the prescribed intensity and 60-75% Tmax as the duration.
ANAEROBIC THRESHOLD TRAINING AND VO2max
Rusko, H. (1987). The effect of training on aerobic power characteristics of young cross-country skiers. Journal of Sports Sciences, 5, 273-286.
Intensive training at anaerobic threshold or higher is the most
effective method for improving VO2max. Low-intensity
continuous training is a better method for improving anaerobic
AEROBIC TRAINING LOAD CHANGES
Gomes, P. S., & Bhambhani, Y. (1996). Time course changes and dissociation in VO2 at maximum and submaximum exercise levels as a result of training in males. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 81.
The responses to aerobic training programs are specific to the activity performed. If workloads are increased every nine training sessions and if intensities are consistently over the ventilatory threshold (VT), significant increases in VO2 at VT as well as at maximum can be observed. These two changes may not be related.
Implication. When training aerobically, the
adaptations for aerobic capacity training occur above the ventilatory
threshold. However, workloads should be consistently maintained for at
least nine sessions before they are further increased. There will
become a time when further increases in VO2max will not
AN OPTIMAL LEVEL OF SPECIFIC INTENSIFIED TRAINING
GIVES BEST RESULTS
Billat, V. L., Petit, B., Koralsztein, J. P., & Fletcher, B. (1997). Overload training at vVO2max does not alter performance at vVO2max. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1389.
This study assessed the value of increasing specific training volume on performance. The influence of a defined increase in training volume (threefold) at the velocity associated with VO2max on performance and heart rate was examined.
Ss (N = 8) participated in four weeks of normal training with one session per week at vVO2max. The specific training session consisted of five sets of repetitions alternating running at vVO2max and 60%vVO2max (a fast-slow alternation). Intensified training consisted of running the alternating sets program three sessions per week.
It was found that normal training increased the velocity associated with VO2max as a result of improved running economy. VO2max, lactate threshold, time to exhaustion at VO2max, or distance run at VO2max did not change. Heart rate decreased significantly. The intensified training produced no new changes. The increased overload was of no benefit to performance or physiological function.
Implication. There is a certain level of
stimulation caused by specific training stimuli that produce
adaptations. Increasing the volume of that stimulation past an optimal
point will not result in any further performance or physiological
gains. This finding is in conflict with common practices of increasing
training volumes of any intensity, almost without limit, in the belief
that extra benefits will accrue. This produces a difficult challenge
for coaches, to hold back on the number of specific intense training
sessions that are required of athletes rather than subjecting them to
excessive unproductive training.
ERYTHROPOIETIN AND EXERCISE
Bodary, P. F., Pate, R. R., Wu, Q. F., & Bodary, J. M. (1996). The effect of exercise intensity on erythropoietin levels following acute exercise in trained runners. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 496.
Well-trained runners (N = 10) were subjected to a variety of exercise bout intensities: high-continuous (90-92% VO2max), high-intermittent, low-continuous (60% VO2max), and rest (control condition). Exercise bouts were one hour and estimated to be of equal energy expenditure. Blood parameters of hemoglobin, hematocrit, red blood cell count, and erythropoietin (EPO) were measured at pre-exercise, and immediately, 4, 12, 24, and 48 hours post-exercise.
It was found that neither moderate nor intense exercise altered EPO in trained athletes.
Implication. EPO changes are one of the
theoretical justifications for altitude training. However, this study
showed that such changes are not an outcome of exercise stress. It
would appear that EPO is not a factor related to performance changes in
already well-trained athletes and therefore, should not be considered
as a possible benefit from altitude training.
STROKE VOLUME RESPONSE ALTERED BY TRAINING
Derchak, P. A., Gavin, T. P., & Stager, J. M. (1997). Different predictors of maximal exercise stroke volume in trained and untrained subjects. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 285.
In a study designed to identify the best non-exercising predictor of maximum stroke volume for both trained and untrained individuals, the following were found.
Implication. Training changes the nature and the response level of stroke volume. Since it plateaus at 80% VO2max it is likely to be a more important aspect of the cardiovascular response to training than previously thought.
MUSCLE FIBERS DETERMINE WORK POTENTIAL
Esbjornsson, M., Sylven, C., Holm, J., & Jansson, E. (1993). Fast twitch fibers may predict anaerobic performance in both females and males. International Journal of Sports Medicine, 14, 257-263.
Males and females with similar training backgrounds were analyzed for anaerobic performance and muscle characteristics. Whether there was any gender difference in the characteristics was also determined.
Muscle biopsies and a 30 sec all out Wingate test on a bicycle ergometer were performed.
Males were higher than females in peak power (44%), mean power (48%), total lactate dehydrogenase activity (33%), and substrate of LD (38%). Anaerobic performance was directly related to the proportion of type II fibers. Females differed only in muscle volume.
Implication. Anaerobic performance is
directly related to the quantity of fast-twitch fibers in muscles. The
relationship is independent of gender while recognizing that females
have less quantity of fibers. Adding further muscle qualities to a
predictive equation does not increase the prediction of anaerobic
CYCLING INTERFERES WITH RUNNING
Gottschall, J. S., & Palmer, B. M. (1997). The acute effects of cycling on running kinematics. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 493.
The effects of an intense bout of cycling on ensuing running kinematics were investigated. Speed, heart rate, and perceived exertion were also measured. This study has relevance for triathlon and cross-training.
Male triathletes (N = 10) completed two trials on separate days. First, a 30-min high-intensity effort on a windtrainer was immediately followed by a 5 km run. Second, Ss completed a 30-min run at the same heart rate as that measured during the cycling bout in the first trial, and then immediately followed with a 5 km run.
After the cycling bout, Ss ran with a shorter stride length and a higher stride frequency, heart rates were higher, and the rating of perceived exertion was lower.
Implication. This investigation demonstrates
the negative effects of cycling on running performance. Although this
effect cannot be removed in a triathlon event, it does demonstrate a
detrimental effect for cross-training advocates. The value of cycling
for running performance must be questioned for uses other than
exercising while injured or if done at low intensity levels as general
CYCLING CROSS-TRAINING IS DETRIMENTAL TO RUNNING
Pizza, G. X., Flynn, M. G., Starling, R. D., Brolinson, P. G., Sigg, J., Kubitz, E. R., & Davenport, R. L. (1995). Run training vs cross training: Influence of increased training on running economy, foot impact shock, and run performance. International Journal of Sports Medicine, 16, 180-184.
After 30 days of normal training, male runners (N = 11) were subjected to 14 days of reduced training (80% of normal). Ss then ran on 10 consecutive days (100% of normal) as well as performing 8 additional morning workouts of the same volume and intensity. The morning sessions were performed on a treadmill or cycle ergometer so that a comparison between specific training and cross-training could be made. Running economy, foot impact shock, and lactate were assessed during a submaximal treadmill run before and after the 10-day period. Following the submaximal assessment, a 5 km time trial on the treadmill was performed.
After cross-training VO2max was significantly higher than after specific run-training indicating a detrimental effect. No significant changes occurred in run performance, resting heart rate, or blood pressure. Both training programs had similar effects on other measures: RER, carbohydrate oxidation, and lactate were significantly lower, and foot impact was significantly higher.
Implication. Cross-training (cycling) in periods of increased run-training loads was detrimental to running economy and is not a beneficial training alternative.
STRETCHING AND EXERCISE RECOVERY
Young, J. C., & Pitt, K. T. (1996). Effect of static stretching on lactate removal after high intensity exercise. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 406.
Active recovery more effectively lowers post-exercise lactate than does passive recovery. Since static stretching requires muscular effort while holding positions, it can be considered a form of active recovery. This study found that static stretching was more effective for promoting recovery than passive recovery but it was not as good as full active recovery.
Implication. Static stretching would be a preferred recovery activity when no other form of active recovery can be performed.
RECOVERY AFTER ANAEROBIC WORK
Gitto, A. T., Rhodes, E. C., Martin, A. D., Taunton, J. E., & McKenzie, D. C. (1996). Relationship of excess post-exercise oxygen consumption to VO2max and recovery rate. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 408.
The rate and magnitude of recovery from supramaximal work were not related to VO2max, but magnitude was related to anaerobic capacity. Recovery rates were similar in each S across varying degrees of work indicating that recovery from anaerobic work is of a fixed rate irrespective of the nature of the work.
Implication. Recovery from anaerobic work will take longer, the larger the anaerobic capacity of the individual. However, recovery rate will be consistent irrespective of the nature of the activity. Recovery from supramaximal efforts can be measured and assumed to be consistent.
ACTIVE RECOVERY SUSTAINS WORK INTENSITY LONGER THAN
Connolly, D. A., & Baker, S. J. (1997). Effects of recovery mode on power output in repeated bouts of short term, high intensity exercise. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1496.
ATP repletion following exhaustive exercise is in the vicinity of 98-99% after three minutes of recovery. This quick recovery is crucial in repeated short bouts of intense work. What occurs in those three minutes could affect the level of recovery.
This study evaluated changes in peak power, total power output, time to peak power, and lactate removal during repeated bouts of high intensity, short duration cycling under conditions of active and passive recovery. Six trials in each condition were assessed.
There were no overall differences between each form of recovery however, the pattern of recovery across trials was different. Active recovery maintained higher levels of total power output longer than did passive recovery.
Implication. Active recovery between short
bouts of intense exercise sustains higher levels of power output than
OBLA PACE REMOVES LACTATE FASTEST
Richardson, M. T., Rinehardt, K. F., Bouchier, N. B., Zoernik, D., Campbell, D., & Cordill, M. R. (1993). Blood lactate clearance at the OBLA intensity. Medicine and Science in Sports and Exercise, 25(5), Supplement abstract 368.
In male swimmers (N = 15) onset of blood lactate accumulation (OBLA) occurred at 51% of maximal resistance in tethered swimming and 70% of maximal heart rate. OBLA pace removes lactate fastest and in less than 15 min. It was found that recovery was fastest when actively recovering at OBLA pace.
Implication. In swimming, recovery is
facilitated by continuous swimming at a velocity that was equal to that
which produced lactate accumulation (OBLA).
WATER-JET MASSAGE AND RECOVERY
Viitasalo, J. T., Niemela, K., Kaappola, R., Korjus, T., Levola, M., Mononen, H. V., Rusko, H. K., & Takala, T. E. (1995). Warm underwater water-jet massage improves recovery from intense physical exercise. European Journal of Applied Physiology, 71, 431-438.
Junior track and field athletes (N = 14) engaged in randomized week-long training of five strength/power sessions. One week used underwater water-jet massage treatments three times for 20 min during the treatment week.
During the treatment week continuous jumping power and ground contact time improved. In the control week serum myoglobin increased.
It was suggested that underwater water-jet massage in connection with intense strength/power training increases the release of proteins from muscle tissue into the blood and enhances the maintenance of neuromuscular performance capacity.
Implication. Water-jet massage could assist
in recovery from intense strength/power training.
AEROBIC TRAINING IMPROVES RECOVERY FROM ANAEROBIC WORK
Cannon, E. W., Rhodes, E. C., Martin, A. D., & Coutts, K. D. (1998). Aerobic training and recovery VO2 kinetics after supramaximal exercise. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 1130.
Untrained males (N = 10) trained aerobically for six weeks. Pre- and post training VO2max and Anaerobic Speed Tests (normalized for individuals) were performed.
After six weeks of aerobic training, VO2max had improved and VO2 recovery components were significantly decreased. There was no relationship between VO2max and VO2 recovery rates.
Recovery VO2 kinetics associated with high intensity anaerobic exercise were decreased through aerobic training. VO2 recovery rates associated with supramaximal anaerobic work do not appear to be related to VO2max but rather, to the type of training experienced.
Implication. Aerobic training improves recovery from anaerobic exercise. This is justification for developing an aerobic training base no matter what the type of strenuous exercise to be performed.
CROSS-TRAINING NOT AS GOOD AS SPECIFIC TRAINING
Foster, C., Hector, L. L., Welsh, R., Schrager, M., Green, M. A., & Snyder, A. C. (1995). Effects of specific versus cross-training on running performance. European Journal of Applied Physiology, 70, 367-372.
The cross-training hypothesis suggests that despite the principle of specificity of training, athletes may improve performance in one mode of exercise by training in another mode. Well-trained (M = 10; F = 20) individuals were placed in an 8-weeks program of enhanced running training or a control group. The enhancement consisted of increasing the work output by 10% through performing either extra running or swimming. The control group followed the basic, non-enhanced running program.
There was a significant increase in running velocity at a lactate concentration of 4mM/l in the enhanced-running group but not in the cross-training or control groups. The swimming/cross-training group improved in arm cranking which is associated with that arm-dominant activity. The running groups did not display any arm adaptation. The only changes that were significant in the cross-training group were physiological measures. There was no change in running performance. This study suggests that muscularly dissimilar cross-training may add to improved specific (running) tests but not to the same degree as increased specific training. Only specific training affected running performance.
Implication. While cross-training
occasionally might show some transfer effects, the size of effects will
be less than those which could be attained by increasing specific
training by a similar amount. Although cross-training "benefits" are
sometimes observed, they usually are in some physiological measures,
and rarely in performance. Thus, cross-training, when it works, is a
very inefficient method for producing slight performance capacity
increases. The emergence of effects in performance is an even rarer
Effects of training at different speeds
WHATEVER HAPPENS AT LOW EFFORTS HAS NO RELATIONSHIP
TO WHAT HAPPENS AT HIGH EFFORTS
Brisswalter, J., Legros, P., & Durand, M. (1996). Running economy, preferred step length correlated to body dimensions in elite middle distance runners. Journal of Sports Medicine and Physical Fitness, 36, 7-15.
Elite distance runners, who were homogenous in terms of VO2max, were tested under two conditions of work intensity:
Many physical dimensions were measured.
The relationships of body dimensions and movement economy to slow running velocity were opposite those with fast running velocity. There was no relationship between economy of movement between the two velocities. In essence, what was important and influential in governing performance at slow velocity was either unrelated or had an opposite effect at the higher velocity.
Mechanisms of adaptation are different according to the velocity of movement. Specific constraints on variables exist for each individual.
Implication. Training effects from one training velocity are not likely to transfer to another velocity. The greater the velocities differ, the more likely it is that factors developed at one speed will affect the other detrimentally.
The factors that govern movement patterns and economy at one training velocity will not be the same at another velocity. This raises the specter of much training being done at less than competition velocity or intensity causing intended performances to be depressed because of the transfer of factors that are negatively related. While there still is a justification for performing much moderate intensity training, such training becomes less desirable as important competitions approach. It is a reasonable hypothesis to suggest, as an important competition approaches, the volume of intended specific-performance training should increase while the volume of non-specific training should decrease and eventually be removed except for initial warm-up and warm-down activities.
When athletes are tested for physiological states
there are many protocols that involve starting at a low intensity and
progressing to high intensity tasks. Such protocols involve continual
alteration of capacities as intensity changes. Just what is being
analyzed when the results of such tests are produced is not clear.
Since those results include outcomes from capacities which are not
desirable for intended competitive performances (the low intensity
factors) it is no wonder that such tests do not have substantial
correlations with high-levels of performance in elite athletes.
CROSS-TRAINING: A MISNOMER
Hawley, J. A., & Burke, L. M. (1998). Peak performance: Training and nutritional strategies for sport. Sydney, Australia: Allen and Unwin.
Cross-training is when an athlete undertakes training in a discipline other than their main sport for the sole purpose of enhancing performance in their main sport. Both scientific evidence and anecdotal reports overwhelmingly indicate that the best way to retain a training effect and improve subsequent performance is to continue using the primary activity mode of competition. There may be some beneficial transfer between activities that have very similar forms of neuromuscular recruitment.
Cross-training is somewhat of a misnomer for a serious single-sport/event athlete and is best left to those multi-event sports that require competitors to be proficient in more than one discipline (e.g., triathlon).
Perhaps the only advantage of cross-training is when an athlete is forced to cease training in the primary activity (e.g., through injury) and there is a need to maintain a general fitness base. In such a circumstance specific fitness adaptation would be lost. The closer the range of motion of the substitute training to the primary activity, the better will be the retention of training adaptation.
However, if the intent of training is simply to maintain physiological fitness then a mix of exercises that stimulate adaptation in the desired physiological capacities would be beneficial. Physiological fitness would improve but there is no guarantee that performance would improve unless the original fitness level was particularly poor.
Implication. Cross-training is not an avenue for improving specific performances once maximal general fitness has been achieved.
INTERMITTENT TRAINING IS MORE DEMANDING ON OXYGEN
TRANSPORT THAN CONTINUOUS TRAINING
Almuzaini, K. S., Potteiger, J. A., & Green, S. B. (1977). A comparison of continuous and split exercise sessions on excess post-exercise oxygen consumption and resting metabolic rate. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1112.
The effect of splitting a 30-min exercise bout into two equal 15-min sessions on excess post-oxygen consumption (EPOC) and resting metabolic rate was determined.
Ss (Males = 10) cycled for 30 minutes at 70% VO2max followed by a 40-min measurement of EPOC. The two 15-min trials were performed with six hours of rest between. Each split-session trial was followed by 20 minutes of EPOC measurement.
The combined magnitude of the EPOCs from the split sessions was significantly greater than from the single session. However, there was no difference in resting metabolic rates between the two protocols.
Implication. Splitting training tasks into
intervals or repetitions will increase the amount of oxygen consumed
and needed to be repaid after each unit when compared to performing the
same distance at the same workload in a continuous manner. Intermittent
training tasks place a greater load on the oxygen transport system than
do continuous tasks.
LENGTH OF REST PERIODS
Stegeman, J. (Translated by J. S. Skinner). (1981). Exercise physiology (p. 259). Chicago, IL: Year Book Medical Publishers.
The placement of pauses during work that exceeds
the threshold for prolonged work is important. Since the course of
recovery proceeds exponentially, that is, the first seconds of the
pause are more effective for recovery than the latter portion, it is
much more appropriate to insert many short pauses than one long pause
in interval training. Lactic acid recovers very quickly in a short
period of time. Longer time periods do not produce much added benefit.
Thus, for prescribing training stimuli of an interval nature, the
athlete should be subjected to a certain level of discomfort through
fatigue, provided with recovery, and the cycle repeated so that work
volume, intensity, and performance consistency are maximized. This is
why interval training is so effective for developing anaerobic
RECOVERY FROM FATIGUE IN REPEATED MAXIMUM EXERCISES
WITH A SHORT INTERIM REST
Casey, A., Constantin-Teodosiu, D., Howell, S., Hultman, E., & Greenhaff, P. L. (1996). Metabolic response of type I and II muscle fibers during repeated bouts of maximal exercise in humans. American Journal of Physiology, 271, E38-E43.
Male Ss (N = 9) performed two 300 sec maximum efforts on an isokinetic cycle machine at 80 rpm. There was a 4 min recovery period between each effort.
The following were found:
Implication. In very high intensity work that places great emphasis on explosive anaerobic work, the recovery of type II (fast-twitch) fibers associated with the work is slower than compared to type I (slow-twitch) fibers. This means recovery intervals between "sprint" or short intense activities have to be longer than those employed for endurance training. The slower recovery of type II fibers warrants greater rest periods.
INTERMITTENT TRAINING SUSTAINS GREATER WORK
VOLUMES THAN CONTINUOUS TRAINING
Billat, V. L., Bocquet, V., Slawinski, J., Demarle, A., Lafitte, L., Chassaing, P, & Koralsztein, J. P. (1999). Intermittent running at vVO2max allows to sustain a longer time at VO2max that severe continuous submaximal run. Medicine and
Science in Sports and Exercise, 31(5), Supplement abstract 275.
This investigation compared time sustained at VO2max in exhaustive exercise under two protocols:
Ss were long distance runners (N = 9) unfamiliar with intermittent training.
Intermittent work provided greater time at VO2max and lower blood lactates than in continuous training.
Implication. Work volumes at VO2max are extended with intermittent training over those achieved with continuous training.
WARM-UPS FOR AEROBIC EVENTS
Shellock, F. G. (1983). Physiological benefits of warm-up. The Physician and Sportsmedicine, 11, 134-139.
Changes derived from a warm-up that is specifically designed for endurance events have been documented. These alterations produce a higher percentage of energy production from aerobic processes because of the facilitation of aerobic mechanisms that occurs after passive warm-up or rest. Ingjer and Stromme (1979) verified these benefits as well as finding that lactic acid levels were lowered during work and in recovery. Shellock (1983) listed the changes.
Implication. Aerobic endurance warm-up activity better
prepares the body for aerobic endurance performance.
THREE TYPES OF WARM-UPS
Ingjer, F., & Stromme, S. B. (1979). Effects of active, passive, or no warm-up on the physiological response to heavy exercise. European Journal of Applied Physiology, 40, 273-282.
Three types of warm-ups were described.
Implications. There are some further considerations with regard to specific warm-up:
MASSAGE DOES NOT CONTRIBUTE ANYTHING TO WARM-UP
Boone, T., Cooper, R., & Thompson, W. R. (1991). A physiologic evaluation of the sports massage. Athletic Training, JNATA, 26, 51-54.
A 30-minute bout of sports massage did not affect central or peripheral responses of healthy males to an 80% VO2max treadmill run.
Implication. Massage, as part of a warm-up,
does not enhance endurance performance.
AEROBIC WARM-UP ENHANCES AEROBIC ENDURANCE RESPONSES
Chwalbinska-Moneta, J, & Hannien, O. (1989). Effect of active warming-up on thermoregulatory, circulatory, and metabolic responses to incremental exercise in endurance-trained athletes. International Journal of Sports Medicine, 10, 25-29.
Male competitive cross-country skiers (N = 10) performed a graded exercise test normally (control) and at least one week later after an active warm-up (10 minutes cycling at 40% VO2max) in a laboratory setting. Various temperature and circulatory responses were recorded.
Deep body temperature and circulatory and ventilatory measures were not affected by the active warm-up. Thermoregulation responses, sweating and skin temperatures, did respond more advantageously after warm-up which attenuated hyperthermia. Anaerobic threshold was also increased after warm-up.
Implication. A moderate amount of submaximal continuous exercise prior to exercise enhances the aerobic endurance capacity of trained endurance athletes.
STRETCHING INCREASES INJURY
Lally, D. A. (1994). Stretching and injury in distance runners. Medicine and Science in Sports and Exercise, 26(5), Supplement abstract 473.
A random sample of 600 marathon entrants was analyzed. It was revealed that 35% greater injuries in the previous 12 months occurred in those who practiced stretching over those who did not.
Implication. Stretching, in marathon
runners, does not prevent injury. Depending on how and when it is
conducted, it may cause minute damages that serve as precursors to
STRETCHING DURING RECOVERY
Burkoer, K. C., & Schware, J. A. (1989). Does postexercise static stretching alleviate delayed muscle soreness? The Physician and Sportsmedicine, 17(6), 65-83.
The use of static stretching as part of postexercise recovery to alleviate muscle soreness was found to be ineffective and no different to a group who did no stretching at all.
Implication. Stretching as a recovery
activity does not reduce muscle soreness.
SPECIFICITY OF TASK DEMANDS
Ariyoshi, M., Tanaka, H., Kanamori, K., Obara, S., Yoshitake, H., Yamaji, K., & Shepard, R. J. (1979). Influence of running pace upon performance: Effects upon oxygen intake, blood lactate, and rating of perceived exertion. Canadian Journal of Applied Sport Sciences, 4, 210-213.
Several general performance protocols for running a middle-distance event were compared. A treadmill (1,400 m; 4 min) run was evaluated at a fast/slow, slow/fast, and steady pace speed distribution.
The fast/slow protocol resulted in a rapid and
sustained increase in oxygen uptake, less lactate accumulation, and a
lower rating of perceived exertion during the final 2 min of the 4 min
RPE AND BLOOD LACTATE
Ross, J. H., Moreau, K. L., Whaley, M. H., Kaminsky, L. A., & Ridenour, T. A. (1996). Comparison of blood lactate concentration and ratings of perceived exertion during two standard treadmill protocols. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 422.
Ratings of perceived exertion (RPE) were assessed at the stages of each of two exercise formats: the Balke and Bruce protocols. Differences in blood lactate concentrations (BLC) and RPE estimates were observed between the two protocols. It was concluded that the RPE differences were due partly to the differences in BLC.
There is a suggestion in this study that RPE may become less reliable as blood lactate accumulates.
Implication. RPE is affected by the lactate
accumulated in a task.
RPE AND BLOOD LACTATE CONCENTRATION
Moreau, K. L., Ross, J. H., Whaley, M. H., & Kaminsky, L. A. (1996). The effects of blood lactate concentration on perception of effort during exercise. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 424.
This study assessed the relationship between ratings of perceived exertion (RPE) and blood lactate (BLC) during graded exercise protocols.
Results suggested that the relationship between RPE and BLC obtained through a graded exercise protocol may not be transferable to the exercise training setting at exercise intensities in the 50-85% range. RPE may not be an effective method for regulating exercise intensity when blood lactates become a noticeable factor.
Implication. The usefulness of RPE may
be best in steady-state exercise when lactate is relatively low, rather
than in graded protocols. When exercise becomes "painful" the pain may
distort the perception of effort and render RPE less reliable.
RPE AND LACTATE MEASURE DIFFERENT FACTORS
Weltman, J. Y., Kanaley, J. A., Rogol, A. D., Hartman, M. L., Veldhuis, J. D., & Weltman, A. (1997). Repeated bouts of exercise alter the blood lactate (Hla) ratings of perceived exertion (RPE) relationship. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1231.
Moderately trained Ss (N = 16) performed two bouts of exercise on two different days. Exercise intensity was the power output associated with 70% VO2peak on a cycle ergometer for a duration of 30 minutes. One bout was performed on 90-minute intervals and the other on 2-hour intervals. Diet and exercise start times were controlled.
Lactate decreased with each successive exercise repetition in each session. RPE-legs and RPE-overall increased within each session. RPE-chest did not change in the exercise session.
RPE did not appear to be related to lactate concentrations. RPE should not be used to produce a specific lactate level in repeated bouts of exercise.
Implication. RPE describes the effort required to perform. It changes independently and often in the opposite direction to lactate levels in repeated bouts of exercise.
TYPES OF FATIGUE
Nadel, E. R. (1985). Physiological adaptations to aerobic training. American Scientist, 73, 334-343.
Nadel (1985, p 334) described the symptoms of fatigue as being related to the progressive inability to supply sufficient energy to the active muscles. Three types of fatigue that correspond to each of the three energy systems involved in exercise were defined.
Asmussen, E. (1979). Muscle fatigue. Medicine and Science in Sports, 11, 313-321.
Power is concerned with the intensity of exercise that can be sustained while work is concerned with the amount of exercise that can be performed.
The maximum intensity of exercise is determined by physiological factors such as the maximum rate of O2 uptake, maximum heart rate and stroke volume, maximum muscle strength, etc. In the case of maximum work, a time factor is involved. Muscle fatigue is the transient decrease in performance capacity of muscles, usually evidenced by a failure to maintain or develop a certain expected force or power.
Fatigue curves vary between individuals and within individuals depending upon the conditions that exist.
Muscle fatigue can occur in two basic mechanisms: (a) central involves proximal motor neurons (mainly in the brain); and (b) peripheral involves within the motor units (i.e., motor neurons, peripheral nerves, motor endplates, muscle fibers).
In peripheral muscle fatigue there are at least two different sites where repeated contractions may cause impairment: the "transmission mechanism" (neuromuscular junction, muscle membrane, and endoplasmic reticulum), and the "contractile mechanism" (muscle filaments).
As the mechanical response of the individual active muscle fibers decline with fatigue, a certain compensation can be achieved by increasing the innervation frequency and/or the number of active motor units. The reasons for the appearance of peripheral muscle fatigue are local changes in the internal conditions of the muscle. These may be biochemical, depletion of substrates such as glycogen, high energy phosphate compounds in the muscle fibers, and acetylcholine in the terminal motor nerve branches, or they may be due to the accumulation of metabolites, such as lactate or electrolytes liberated from the muscles during activity.
In short-term maximal or near-maximal isometric contractions, it is highly improbable that a general depletion of the energy stores should be the direct cause of exhaustion. The only substances that specifically undergo a significant decrease are the high energy phosphates, especially creatine phosphate (CP). The decrease of high energy phosphates is not due to a depletion of energy stores. It is due to a too low rate of energy transfer from the stores to the ATP and CP. This slowing, presumably of enzymatic processes, might be caused by the concomitant increase in muscle lactic acid, causing a pH decrease. Accordingly, lactic acid might be termed a "fatigue substance." However, there are several other possibilities particularly if transmission fatigue is present. Thus, both the contractile and transmission mechanism may be impaired by continuous muscle activity.
Summary. Peripheral muscle fatigue, defined as a transient decrease in a muscle group's capacity for exercise, can be purely peripheral (i.e., located distally to the motor neurons). The site may be the transmission mechanism, and the cause may be the depletion of some necessary substance(s)) and/or the accumulation of catabolites or other substances set free by the muscle activity.
The "Setchenov phenomenon" (1903): when sawing exhausts the muscles of one arm, they recover faster if the other arm is exercised during the rest pause rather than following rest alone. This was explained as a "recharging with energy" of fatigued nerve centers brought about by afferent nerve impulses from the active non-fatigued arm. The other activity constituted a diverting activity that produced the accelerated recovery of the central mechanism.
It is explained as follows. During muscle fatigue, feedback of nerve impulses from the fatigued muscles impinges on a part of the reticular formation and causes an inhibition of voluntary effort. Diverting activity, on the other hand, produces an increased inflow of impulses from non-fatigued parts of the body to the facilitatory part of the reticular formation, thus shifting the balance between inhibition and facilitation in a facilitatory direction.
Central fatigue is also an expression of lowered arousal. During fatigue studies, EEGs show a gradual appearance of the characteristic alpha-rhythm as fatigue progresses. The introduction of diverting activity makes the alpha-rhythm disappear. Alpha-rhythms are a signal of lowered arousal level in the brain, and usually are found when subjects close their eyes and disappear when the eyes are opened.
Central fatigue is caused by an inhibition elicited by nervous impulses from receptors (probably some kind of chemoreceptors) in the fatigued muscles. The inhibition may act on the motor pathways anywhere from the voluntary centers in the brain to the spinal motor neurons. This kind of fatigue should manifest itself by a decrease in the outflow of motor impulses to the muscles. There are several good reasons for assuming this central component is the result of central inhibition called forth by signals from the fatigued muscles. This inhibition, most likely originating in the reticular formation, may itself be inhibited or counteracted by other signals of peripheral or central nervous origin.
Summary. Peripheral or central fatigue
may appear separately or combined, depending on the specific situation.
Any one link in the long chain from the voluntary motor centers in the
brain to the contractile filaments in the single muscle fibers may be
the weaker and thus most direct cause of muscle fatigue. Prevention and
treatment of voluntary fatigue must be adapted to these complexities.
Rushall Thoughts, 1990.
Anaerobic metabolism may occur at the beginning of relatively high intensity exercise, when the oxygen transport mechanisms of the body have not had sufficient time to meet the energy requirements. Anaerobic metabolism may also occur when the aerobic metabolic pathways are over-stimulated so that certain key enzymes are over-taxed and not able to keep up with the required pace of converting one substance to another in the long chain of events that constitutes aerobic metabolism. This may happen even when there is sufficient molecular oxygen provided to the muscle cell. This latter feature is what is known as local fatigue, a feature that occurs in sports such as swimming, kayaking, and cycling, when specific large muscle groups work very intensely while the rest of the body works submaximally, that is, aerobically. In such situations, the athlete might not breathe very heavily, but at the localized site is working excessively. The lactic acid that is produced through the intensely working muscles is consumed by various organs (e.g., liver, heart) and submaximally working muscles. Thus, in sports where local fatigue is high it is possible to work those isolated muscle groups for a longer period more intensely than would be possible if the total body was working at a similar high intensity. Usually, higher levels of localized pain can be tolerated than can be endured with general fatigue.
THE WORK OF RESPIRATION DOES NOT LIMIT PERFORMANCE
Nava, S., Zanotti, E., Rampulla, C., & Rossi, A. (1992). Respiratory muscle fatigue does not limit exercise performance during a moderate endurance run. Journal of Sports Medicine and Physical Fitness, 32, 39-44.
Well-trained athletes were evaluated for respiration factors before, during, and after an all-out 17 km run. It was found that respiratory "strength" and other factors remained constant during the task. Exercise in well-trained individuals does not cause the work of respiration to become a debilitating factor.
Implication. The work of breathing is not
a limiting or debilitating factor in well-trained athletes over
moderate-distance endurance tasks.
LEARNING IS BEST ACCOMPLISHED IN A NON-FATIGUED STATE
Barnett, M. L., Ross, D., Schmidt, A., & Todd, B. (1973). Motor skill learning and the specificity of training principle. Research Quarterly, 44, 440-447.
Fatigue alters the recruitment pattern and intensity of work of a muscle's motor units. If one considered an interpretation of the specificity of training principle, that training should be done under the conditions of appropriate fatigue, it would seem that "criterion" conditions could be defined.
In this study, two models of skill training were compared. The first was the "criterion" condition that employed appropriate stress, while the other was the "optimal" condition that was to generate the highest level of performance practice.
Although the results of skill learning were not significantly different, which could be due to an artifact of the experimental design used, the data indicated that the non-fatigued learning condition was superior to fatigued learning.
Implication. When learning a skill it is best to practice in non-fatigued conditions whether or not the skill would eventually be performed in fatigue. This would seem to be a contradiction of the specificity principle but that is a wrong impression. The establishment of neuromuscular skill patterns is best achieved in non-fatigued states. When a skill is overlearned to a desired level of proficiency then it can be practiced under difficult and environmental specific cues (e.g., crowd noises).
The principle of specificity should never be used to
override the dictates of a basic principle of learning: initial
learning occurs best in the absence of distractions and fatigue.
CHO ENERGY DEPLETION SLOWS DOWN NEURAL ACTIVATION
Bauer, R. S., Hatfield, B., Haufler, A., Lockwood, P., & Hung, T. (1997). Effect of exercise-induced hypoglycemia on CNS activation in elite cyclists. Medicine and Science in Sports and Exercise, 29(5), Supplement abstract 1275.
The effects of glycogen levels on neural functioning in elite cyclists (N = 6) were evaluated under two conditions: hyperglycemia as induced by carbohydrate feedings and placebo.
It was found that as glycogen levels were eroded, greater neural deactivation occurred. This showed that not only are energy resources for exercise removed with fatigue and lowered glycogen levels, but so are the resources for neural functioning, causing less-efficient and less powerful neural activation.
Implication. Carbohydrate loading has
two important effects. First, it extends the fuel supply for endurance
exercise allowing individuals to sustain effort levels for longer
periods. Secondly, it extends the time the central and peripheral
neural systems can maintain their highest levels of activation. As
fatigue due to energy supply depletion is incurred it becomes
increasingly difficult to produce a maximum intensity movement.
RUNNING ECONOMY MOST RELATED TO RACING PERFORMANCES
Northius, M. E., Leon, A. S., Serfass, R. C., Walker, A. J., Crow, R. S., & Jacobs, D. R. (1999). High responders vs. low responders in cross country running training. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 1387.
This study attempted to locate variables that differentiate between high-responders (large improvements in race velocity) and low-responders (little to no improvements in race velocity) among Division I collegiate cross country runners (M = 6: F = 10) who participated in identical training programs. Two analytical multivariate models were used:
Changes in maximal lactate production and running
economy were significantly related to changes in racing velocity. The physiology
model explained 70% of variance in change in running performance
velocities while the performance
model explained 76%. Change in running economy accounted for ~67% in
Heart rate became less economical during the season (-3.5%) although maximal lactate increased by 36%. This suggests some aerobic capacity might be sacrificed with anaerobic training.
Implication. Running economy is the best predictor of competitive running performances. As many factors as possible should be considered when evaluating performances. It is most appropriate to develop concepts of training response patterns on an individual basis. In this study, all Ss trained similarly, but responded individually.
PHYSIOLOGICAL IMPROVEMENTS SHOULD NOT BE EXPECTED
DURING THE COMPETITIVE PHASE
Mero, A., Rusko, H., Peltola, E. Pullinen, T., Nummela, A., & Hirvonen, J. (1993). Aerobic characteristics, oxygen debt and blood lactate in speed endurance athletes during training. Journal of Sports Medicine and Physical Fitness, 33, 130-136.
"Speed endurance athletes" comprised 20 male 400-m sprinters and hurdlers. Ss were tested at the beginning of March, the end of May, and the end of August. The latter measurement period was the competitive phase.
Aerobic and anaerobic threshold and maximal oxygen uptake measured on a treadmill decreased from the end of May to the end of August. Time to exhaustion improved from March to May and then did not change. The highest level of oxygen debt was measured in May. Peak blood lactate following anaerobic work, increased from March to May and then remained stable.
Good athletes differed from poorer athletes in time to exhaustion, 100-m time, and VO2max.
During the competitive period, aerobic status declined while anaerobic work characteristics remained high. Testing of anaerobic adaptation in the competitive period should be particularly specific.
Implication. Aerobic status declines
when trained 400-m runners experience an extended competitive period.
Anaerobic factors remain stable and high. Physiological improvements
should not be expected once the competitive phase of training begins.
THE HARDER A SWIMMER TRAINS, THE SLOWER WILL BE
Fitts, R. H., Costill, D. L., & Gardetto, P. R. (1989). Effect of swim exercise training on human muscle fiber function. Journal of Applied Physiology, 66, 465-475.
The effects of a typical collegiate swim-training program and an intensified 10-day training program on deltoid muscle fibers were evaluated.
A 10-week training program produced an almost twofold increase in the mitochondrial marker enzyme, citrate synthase, in the muscle fibers. Peak tension of single fibers was not altered by either the usual or intensified training experiences. No differences in peak tension were observed between type I (slow-twitch) fibers or type II (fast-twitch) fibers. Fast-twitch fibers contracted almost five times faster than slow-twitch fibers.
Normal training increased the contractile speed of the slow-twitch fibers and decreased that of the fast-twitch fibers. The increased training load further and significantly decreased the contractile speed of the fast-twitch fibers. After a period of detraining, both fiber types returned to control/normal levels.
Implication. Normal/tolerable swimming
training does not alter the force-velocity relation in either type I or
II fibers. Intensified training reduces the contractile velocity of
type II fibers further. The harder a swimmer trains, the poorer will
become sprint-swimming performances. Tapering will produce a recovery
from depressed sprinting performances.
TRAINING VOLUME, NOT TYPE, IS ASSOCIATED MOST WITH
SPRINT PERFORMANCE IMPROVEMENTS
Reid, A. K., & Sleivert, G. G. (1999). The effects of concurrent aerobic and anaerobic training versus sequenced training on 80 s cycling. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 789.
This study investigated the influence of concurrent versus sequenced aerobic and anaerobic training on supramaximal cycling performance. Trained cyclists of both genders (N = 24) trained for a total of 19 weeks. The first five weeks established a stable baseline level of fitness. Then Ss were randomly assigned to either a concurrent 12-week aerobic-anaerobic training group, or a sequential 6-week aerobic, 6-week anaerobic training group. Sixty training sessions were completed, at a rate of five training sessions per week. Assessments were made at the end of each 6-week block of training.
Both groups improved similarly in performance after 12 weeks of training. However, the way in which the 80-s test was completed differed between the groups. The concurrent group improved mainly because of an increase in maximal power at each stage of the test. No changes in aerobic function were revealed. The aerobic training group demonstrated changes associated with metabolic factors.
The order or mix of anaerobic and aerobic training does not differentially affect cycling performance. Rather, the total training volume is associated most with performance changes.
Implication. Training volume, not type of
training, is associated most with sprint performance improvements in
TRAIN FAST TO RUN FAST
Smith, T. P., McNaughton, L. R., & Coombes, J. S. (1999). Effects of a 4-week interval training program using vVO2max and Tmax on performance in middle distance athletes. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 1391.
Velocity at VO2max (vVO2max) and maximum time at that velocity (Tmax) are used to design individual training programs. Previous work showed that significant performance improvements resulted from interval training a vVO2max and 60% Tmax. This study evaluated the effects of training for four weeks with an exercise intensity between 60-75% of Tmax as the interval duration. Trained male middle-distance runners (N = 8) were measured for physiological factors, a 3000m running time-trial, and three treadmill tests to determine Tmax. Training was on a motorized treadmill. Ss were re-tested following training.
Significant increases in average vVO2max, Tmax, and VO2max were recorded after training. The 3000m time-trial performances were significantly improved.
Implication. As the pace of training approaches race velocities, running velocity and physiological adaptations improve.
RESISTANCE TRAINING CAN BE UNDERTAKEN CONCURRENTLY
WITH RUNNING TRAINING
Nicholson, R. M., & Sleivert, G. G. (1999). Impact of concurrent resistance and endurance training upon distance running performance. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 1559.
The impact of concurrent resistance and endurance training on 10-km running performance in a simulated competitive situation was investigated. Runners (M = 19; F = 11) were matched and randomly assigned to an experimental (running and resistance) or control (running) group. Ss performed the same training program for 21 weeks, running from 5 to 8 times per week for 30 to 90 minutes at a heart rate intensity ranging from 75 to 95% of maximum. Resistance training involved 3 x 8 repetitions per exercise (intensity level of 8-RM), except for abdominals (15 repetitions). Testing occurred during weeks 3, 9, 15, and 21.
The resistance group improved significantly in running time (3.5%), VO2max, lactate threshold velocity, and upper and lower body strength. The running-only group improved in running time (2.2%) and lower body strength.
The addition of resistance training did not adversely affect the beneficial effects of running training. It added some extra fitness improvements and might be considered as a beneficial training addition for the basic preparatory phase of a running specialist's annual training plan or by individuals interested in a more generalized fitness program.
Implication. Resistance training does not
interfere with running training improvements.
ANAEROBIC TRAINING PRODUCES QUICKER CHANGES THAN AEROBIC TRAINING
Villani, A. J., Fernhall, B., & Miller, W. C. (1999). Effects of aerobic and anaerobic training to exhaustion on VO2max and exercise performance. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 1093.
This study compared the effects of exhaustive aerobic continuous training (AT) and exhaustive anaerobic interval training (ANT) on VO2max and Wingate Power Test scores. Ss (N = 15) exercised three times per week for four weeks, training sessions being of equal duration.
The ANT group increased time to fatigue at VO2max, while AT showed no significant change. ANT also improved significantly more than AT in peak power, 30-s power output, and total work output in the Wingate Test.
Implication. Exhaustive anaerobic interval
training produces quicker physiological adaptations than does
continuous aerobic training.
ANAEROBIC INTERVAL TRAINING IS NOT THAT WELL UNDERSTOOD OR DEFINED
Billat, L. V. (2001). Interval training for performance: A scientific and empirical practice. Special recommendations for middle- and long-distance running. Part II: Anaerobic interval training. Sports Medicine, 31, 75-90.
Anaerobic interval training is probably best described as "repeated maximal sprint training" or "supramaximal sprint training." It takes various forms and has vastly different training effects depending upon the intensity and duration of the work and the duration of the rest period. Consequently, there is little consensus in the literature with many studies varying too many factors, which obscure the actual mechanisms being used. Much of this form of training aims to improve anaerobic function, particularly glycogenolysis, but aerobic contributions and adaptations are also involved.
Fixed Work-rate Intervals
With short bouts (10-30 seconds) of intense exercise (150+% of vVO2max), it is the duration of the rest period that determines the energy systems employed. When very short rests (1:1 work:rest 10-15 seconds) are used, the adaptation is primarily aerobic. When rest periods exceed 30 seconds, the length of time it takes to allow the phosphagen pool to be resynthesized after very short maximum sprint efforts, work is primarily but not exclusively anaerobic. Athletes can perform many repetitions without increasing lactate above 2.5 mmol/kg. Thus, explosive intense effort interval training will elicit different metabolic characteristics depending upon the length of the rest interval employed.
Using short-short (ultra-short) interval work (10-15 seconds), the contribution of glycogenolysis to the total energy demand is considerably less than if work of a similar intensity was performed continuously (30-60 seconds). Supramaximal fixed work-rate interval training is most likely to tax both anaerobic and aerobic energy systems close to their maximum capacities.
Fixed Intensity Intervals
Typically, in this form of training the level of performance declines in the latter stages of the interval set. Most researchers have used longer work intervals (>30 seconds) and work:rest ratios of 1-4 or greater. With each successive repetition, the role of aerobic energy increases, particularly if CP has not fully resynthesized. In this form of interval training, CP is depleted extensively and takes longer to fully "recharge."
If coaches believe that longer duration sprints (>30 seconds), at or near maximum velocity, train the anaerobic pathways they are mistaken. With each successive trial, the role of aerobic metabolism increases, in concert with a decline in performance quality. One could assert that in repeated maximal sprint work, that if performance declines the contribution of anaerobic energy is relatively low and the aerobic energy contribution is quite high. In maximal sprint training, the rest periods have to be long enough to allow CP to be fully replenished so anaerobic energy sources will be maximally available for each repetition.
"To increase the glycolysis pathways, which account for 40 to 50% of the energy necessary to cover 100m, the intermittent training consists of a series of 100, 120, and 150m runs at 88 to 90% of the best performance with a passive rest of 5 to 6 minutes between each bout. However, in this protocol, it has been demonstrated that during passive rest almost all the CP was resynthesized after 4 minutes (from 19.8 to 36.9 mmol/kg dry muscle, instead of 39 ± 3.2 mmol/kg). The half time of CP resynthesis is 170 seconds." (p. 78)
To improve performance in competitions that last one minute (e.g., 1 km in track cycling, 100 m in swimming, 400 m in running), events that are normally performed at >150% VO2max, it is important to practice aerobic interval training, since the aerobic metabolism contribution is quite substantial.
"It is well know that both anaerobic pathways -- lactic (glycolysis) and alactic (CP degradation) -- are activated instantaneously at the onset of maximal activity. However, the ability to repeat maximal sprints depends on the duration of recovery, which does not have the same effect on the two anaerobic pathways. The resynthesis of CP depends on the endurance level of the participant" (p. 78). Glycogenolysis is largely elicited in supramaximal sprints, the work intensity being well above that which allows energy to be derived from lipids.
There is a relationship between the length of the supramaximal work bout and rest. The work:rest ratios increase as the duration of work increases. For example, in the sport of swimming, 10 seconds of work can be very easily balanced by rest periods of 10-20 seconds. However, one minute of appropriate work (i.e., near race-pace for the distance covered), would require more than five minutes of rest if a reasonable approximation of the first performance is to be repeated. Not only does the rest interval change with duration of supramaximal work, but also the number of repetitions is inversely proportional to the duration of work. To derive the most appropriate training stimulation, a coach has to determine these factors along with each individual's receptivity to this form of training. [The tendency seems to be to attempt to do too many repetitions, the latter experiences being largely detrimental to the training objectives and the individual's welfare.]
Long-term Physiological Effects
Many studies considering the long-term physiological effects of supramaximal sprint training have demonstrated an improvement in VO2max. However, there is a gender-specific response to achieve that state. Changes in aerobic power and submaximal heart rate for females are independent of repetition frequency, distance, and intensity. For men, it has been shown that training intensity, rather than frequency or distance, is the most important factor for improving VO2max.
One should not conclude that supramaximal sprint training is inefficient for improving anaerobic capacity. It has to be performed at a level of power output that greatly exceeds that associated with VO2max. Many studies have not worked subjects hard enough to stimulate the full recruitment of anaerobic energy or type II muscle fibers. If an athlete does not work with sufficient intensity to place the work well above the VO2max level, it is likely that training will be mainly aerobic in its effects. The most useful practical index of achieving significant anaerobic stimulation in a training bout is the demonstration of high lactate levels.
There is an important relationship between type I (aerobic) and type II (anaerobic) muscle fibers. Type I fibers are more involved in the removal of accumulated lactate than are type II fibers. To increase alactic anaerobic metabolism, supramaximal sprint training acts: (a) by increasing the ability to decrease CP as rapidly as possible if rest intervals are of sufficient length to allow the restoration of the CP reserve (avoiding the involvement of anaerobic glycolysis); and (b) by increasing the ability to replenish the CP reserve as quickly as possible. To accomplish the second effect, it is necessary to have muscle fibers with a high oxidative capacity, that is a trained aerobic base. However, when rest intervals are insufficient, anaerobic lactic metabolism (glycolysis) is increasingly involved. The resulting acidosis could impair CP production (via mitochondrial creatine kinase) during recovery (p. 80).
One valuable contribution of aerobic training to sprinting is the development of the capacity to replenish, most probably in an accelerated manner, CP reserves.
The amount of supramaximal sprint training required to produce desirable physiological changes is not great [in running]. Three to four repetitions of five minutes of effective high intensity interval training per week (~20 minutes) can result in an increase in both glycolytic and oxidative muscle enzyme activity, maximum short-term power output, and VO2max. The challenge for coaches is to NOT OVERDO this form of training. It is particularly debilitating when experienced in excessive amounts.
For events that are dominantly aerobic, but where an increased anaerobic contribution is required, such as when running the last lap of a 10K race in 52 seconds, interval training using short all-out bouts of exercise that elicit the glycolytic pathway should be used. Normally, supramaximal training of longer duration, such as one minute at ~130% of vVO2max with rests of five minutes is appropriate. Reports have suggested this training three times a week for eight weeks can produce pronounced changes.
This type of training does appear to be enhanced when diet is supplemented with creatine. Benefit is derived from a higher availability of phosphate or produced by an increased rate of CP resynthesis during recovery periods.
When training is designed to induce both anaerobic and aerobic energy supply, presumably because that is the "mix" of energy in competitions, it might be necessary to perform sets of intervals of different duration and rest periods. The short-task short-rest work will stimulate aerobic adaptation, whereas long work and extra long recovery will stimulate a greater amount of anaerobic adaptation along with the ever-present aerobic adaptation. If the tasks are performed at the same maximal velocity/intensity, neuromuscular patterning will be "conditioned" as well.
Implications for Training
Throughout the remainder of the paper, the author suggests various considerations for training. They are interpreted below and are tempered by this reviewer's own knowledge of these matters.
HIGH-REPETITION STRENGTH AND SPRINT TRAINING
INCREASES MUSCULAR ENDURANCE BUT NOT SPEED
Newberry, J. E., & Flowers, L. (1999). Effectiveness of combining sprint and high-repetition squat resistance training in anaerobic conditioning. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 1384.
Three groups of 12 males underwent different training regimens: sprint training alone (12 x 40-yd, 25-second rest, three days per week), sprint training plus strength training (5 x 12 repetitions of 50% 1-RM, two days per week), and no training (control).
Both training groups were significantly better than the no training group. The resistance-training group displayed a significantly higher percentage of maximal velocity than the sprint-only group. There were no significant differences between groups in sprint speed.
Implication. High-repetition strength training added to sprint training, increases muscular endurance, but not speed. This form of training would be best suited to activities that require repetitious sprint activities.
ENDURANCE TRAINING IN TOP CLASS ROWERS
Hartmann, U., & Mader, A. (1966). Oxygen uptake, heart rate and lactate during endurance training in top class rowers. Medicine and Science in Exercise and Sports, 28(5), Supplement abstract 744.
In 12 elite German males it was shown that three hours of rowing per day can only be completed at a very low level of intensity with only a few high intensity loads. This leads to a training of about 55-60% of the total training or 85-94% of on-the-water training with an intensity of less than 2 mM lactate.Implication. Most rowing training will be at a low effort demand and will produce non-race-specific aerobic adaptation. When speed and more anaerobic work is required an emphasis will have to be placed on recovery otherwise excessive overloading will result. The capacity of rowers to work "hard" seems to be less than is popularly espoused.
THREE MONTHS IS ABOUT ALL THAT IS NEEDED TO ESTABLISH
AEROBIC ADAPTATION IN SWIMMERS
Bonifazi, M., Bela, E., Lupo, C., Martelli, G., Zhu, B., & Carli, G. (1998). Influence of training on the response to exercise of adrenocorticotropin and growth hormone plasma concentrations in human swimmers. European Journal of Applied Physiology, 78(5), 394-397.
This study evaluated the response of adrenocorticotropin ([ACTH]) and growth hormone ([GH]) concentrations to a typical aerobic swimming set during a training season.
Nine top-level male endurance swimmers (age range 17-23 years) were tested during three training sessions occurring 6, 12 and 18 weeks after the beginning of the season. During each session, after a standard warm-up, the swimmers performed a training set of 15 x 200-m freestyle, with 20 s rest between repetitions, at a predetermined individual speed. Blood samples were collected before warm-up and at the end of the training set. A few days before each session, the individual swimming velocity corresponding to the 4 mmol/l blood lactate concentration was assessed as a standard of aerobic performance.
Aerobic training affected velocity levels, which
were highest 18 weeks after the beginning of the season. At the same
time, while [ACTH] response was attenuated, [GH] response was enhanced.
These results could be considered as adaptations to the exercise
intensity. These adaptations seemed to have occurred between the 12th
and 18th weeks of the training season.
REPETITIONS MAY BE CONSTANT BUT THEY INCREASINGLY
DEMAND MORE AEROBIC ENERGY
Smith, J. C., Kjeisers, N. L., Kanteebeen, M., Williams, C. S., Hughes, J. E., & Hill, D. W. (1998). Metabolic responses during repeated bouts of cycle ergometer exercise at critical power. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 212.
It is often assumed that the energy demands in a single bout of interval exercise will be the same across repetitions. Ss (N = 7) were tested for physiological and performance factors and then performed five 6-minute repetitions at critical power with 2-minute recovery periods.
Across the five repetitions, there were no differences in peak VO2 or VO2 kinetics. However, the aerobic contribution increased in a linear fashion across repetitions.
Implication. Interval training
employing predominantly aerobic work increases the demands for aerobic
energy on each successive repetition. For specific training effects to
be achieved, a coach has to determine whether the early or late
repetitions match event-specific demands and emphasize those trials. To
achieve the greatest amount of specific effects variable interval sets
might have to be used.
ENDURANCE GAINS COME FROM IMPROVEMENTS IN EFFICIENCY
OF FIBER USE
Horowitz, J. F., Sidossis, L. S., & Coyle, E. F. (1994). High efficiency of type I muscle fibers improves performance. International Journal of Sports Medicine, 15, 152-157.
The extent to which differences in muscle fiber composition and efficiency influence endurance performance in competitive cyclists was determined. Biopsies of the vastus lateralis determined the percentage of Type I (slow-twitch) and Type II (fast-twitch) fibers. Endurance trained cyclists (N = 14) cycled on an ergometer for one hour at the highest tolerable work rate. Ss were divided into two groups: High Type I fiber group (>56% Type I), and Normal Type I fiber group(38-55% Type I). Physiological response measures during the cycling task were obtained.
The High group was able to maintain 9% higher power output than the Normal group. Gross efficiency was therefore higher in the High group than the Low group.
It was concluded that a high percentage of Type I muscle fibers improves endurance performance ability by significantly increasing the power output generated for a given rate of oxygen consumption and energy expenditure.
Implication. Endurance athletes have an "edge"
if they have a higher proportion of Type I fibers in their musculature.
HIGH LACTATE LEVELS AT TRAINING COMPROMISE AEROBIC PERFORMANCE
Simoes, H. G., Campbell, C. S., & Kokubun, E. (1998). High and low lactic acidosis training: Effects upon aerobic and anaerobic performance. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 932.
Two groups of four volunteer runners trained similarly for four weeks. During that period, one group trained three times per week eliciting blood lactate concentrations of at least 10 mM and the other maintained lactate levels below 6 mM for a similar number of training sessions. Before and after the training period, Ss were tested for an all-out 3,000 m run, 4 mmol/l threshold, steady state heart rate while running at 200 m/min velocity, mean velocity in 5 x 30-m sprints, mean velocity in a 60-m sprint, and mean velocity in a 300-m run.
The low-acidosis training group showed anaerobic gains, an increase in 300-m velocity, and aerobic improvement with a lower heart rate during the 200m/min run and non-significant faster 3,000-m time. The high-acidosis training group also showed anaerobic gains with higher velocity and lactate levels in the 300-m run. However, aerobic performance was compromised. Time for 3000-m run was slower and a higher heart rate was evidenced in the 200 m/min run.
It was concluded that high acidosis training compromises aerobic fitness.
Implication. Too much lactate tolerance (high acidosis) training can cause aerobic performance to decline. Anaerobic training that only stimulates moderate accumulated lactate levels enhances anaerobic performance and maintains aerobic fitness.
INSPIRATORY MUSCLE TRAINING IS USELESS FOR ENDURANCE
Hanel, B., & Secher, N. H. (1991). Maximal oxygen uptake and work capacity after inspiratory muscle training: A controlled study. Journal of Sports Sciences, 9, 43-52.
The effect of inspiratory muscle training for 10-min, twice per day, for 27.5 days was evaluated. Ss were divided into a training group (N = 10) and a "sham" training group.
Increased maximal inspiratory pressure, and a slight decrease in breathing frequency, were observed in the training group but not in the control. There were no changes in VO2max, ventilation during maximal exercise, peak expiratory flow, forced expiratory volume in one second, or for vital capacity in either group. Maximum distance run increased by 8% in the training group and 6% in the sham group.Implication. Inspiratory muscle training does not improve many physiological factors or endurance perform
ENDURANCE-TRAINED ATHLETES HAVE HIGHER BLOOD VOLUMES
AND ENHANCED DIASTOLIC FILLING OF THE HEART
Krip, B., Gledhill, N., Jamnik, V., & Warburton, D. (1997). Effect of alterations in blood volume on cardiac function during maximal exercise. Medicine and Science in Sports and Exercise, 29, 1469-1476.
The effects of manipulating blood volume on cardiac function in endurance trained (N = 6) and untrained Ss (N = 6) were examined. Both groups were examined in a control condition. The endurance-trained Ss were then evaluated after having blood volume reduced by 500 ml while untrained Ss had blood volume expanded by 500 ml.
In normal circumstances endurance trained athletes had significantly greater blood volume, maximal diastolic filling rate, maximal ventricular emptying rate, stroke volume, cardiac output, and maximum aerobic capacity (VO2max). When blood volumes were manipulated these differences disappeared.
Implication. Changes in stroke volume and cardiac output are attributable to changes in blood volume, which enhances diastolic filling.
ULTRA-SHORT INTERVAL TRAINING THE BEST FORM OF
COMPETITION-SPECIFIC AEROBIC ADAPTATION AND NEUROMUSCULAR PATTERNING
Rushall, B. S. (1999). Programming considerations for physical conditioning (page 2.3). Spring Valley, CA: Sports Science Associates
Ultra-short interval training. This form of training is based on the principle that sufficiently short intervals of intense work do not produce lactic acid accumulation. It is appropriate for developing alactacid and aerobic endurance and provides the opportunity for specific skill training at competition intensity. It is used for training phases where specific training is important. When this work is alternated with short rest periods, it is possible to complete a large amount of training at competition quality. For example, a 1:1 work/recovery ratio of periods totaling 20 seconds can be sustained in trained swimmers at 200-meter competition quality for at least 30 minutes. However, when the same work/recovery ratio is maintained but the duration of the task is increased to 1 minute, performance deteriorates quite noticeably in the latter half of the task. Ultra-short intervals do not produce lactic acid accumulation. It is when lactic acid accumulates that fatigue becomes devastating and adequate recovery then takes a markedly greater proportion of time.
Examples of ultra-short training stimuli for swimmers are:
across pool (20 m)
100-m race pace
remainder of 20 sec
across pool (20 m)
100-m race pace
remainder of 20 sec
In these examples, the swimmer starts every repetition on a 20-second interval, the rest period being that time remaining from 20 seconds after each effort.
Implication. This is the best form of training for developing competition specific aerobic adaptation and neuromuscular patterning.
TYPE II FIBERS (POWER) ARE MOST AFFECTED BY A TAPER
Trappe, S., Costill, D., Lee, G., & Thomas, R. (1998). Effect of swim taper on human single muscle fiber contractile properties. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 220.
Changes in the contractile properties of both type I and IIa (fast-twitch oxidative) fibers of the deltoid muscle in swimmers (N = 6) were observed prior to and following a 21 -day taper.
Type IIa fibers are more affected by a taper than are type I fibers.
Implication. This is basic physiological evidence to support Costill's often said proposal that taper affects power more than it does endurance. Since this study only assessed one feature of a taper, it should not be concluded as being the only feature to change.
Critical physiological factors for performance in running are maximal oxygen consumption (), fractional utilization and running economy. While Kenyan and Caucasian elite runners are able to reach very high, but similar maximal oxygen uptake levels, the of black South African elite runners seems to be slightly lower. Moreover, the studies of black and white South African runners indicate that the former are able to sustain the highest fraction of during long distance running. Results on adolescent Kenyan and Caucasian boys show that these boys are running at a similar percentage of during competition. Kenyan elite runners, however, appear to be able to run at a high % of which must then have been achieved by training. A lower energy cost of running has been demonstrated in Kenyan elite runners and in untrained adolescent Kenyan boys compared to their Caucasian counterparts. In agreement with this are the results from studies on black South African elite runners who have shown similar low energy costs during running as the Kenyan elite runners. The good running economy cannot be explained by differences in muscle fibre type as they are the same in Kenyan and Caucasian runners. The same is true when comparing untrained adolescent Kenyan boys with their Caucasian counterparts. A difference exists in BMI and body shape, and the Kenyans long, slender legs could be advantageous when running as the energy cost when running is a function of leg mass. Studies comparing the response to training of Kenyans and Caucasians have shown similar trainability with respect to , running economy and oxidative enzymes. Taken all these data together it appears that running at a high fractional and having a good running economy may be the primary factors favouring the good performance of endurance athletes rather than them having a higher than other elite runners. In addition to having the proper genes to shape their bodies and thereby contributing to a good running economy, the Kenyan elite runners have trained effectively and used their potential to be in the upper range both in regard to and to a high utilization of this capacity during endurance running.
MEN TOLERATE HIGHER LEVELS OF PAIN THAN WOMEN
Koltyn, K. F., Focht, B. C., Ancker, J. M., & Pasley, J. (1998). The effect of time of day and gender on pain perception and selected psychobiological responses. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 30.
Pain threshold, pain ratings, and selected psychological (POMS, STAI) and physiological measures were recorded (M = 15; F = 14). Finger pressure tolerance served as the pain stimulus.
Men had significantly higher pain thresholds than women. Women had significantly higher pain ratings and heart rates. Time of day influenced temperature, systolic blood pressure, and the POMS measure of vigor. Pain measures were not affected by time of day.
Implication. Perceptions of workloads and
their tolerance will differ between men and women.