“The greatest problem in all endurance sports, including swimming . . . is to find the correct intensity of training for each individual. . . . . A sprinter must devote approximately 30% and a distance swimmer 60% of all training to the improvement of aerobic capacity . . . . If training is undergone at too low or too high an intensity, it will have a particularly negative effect on total conditioning.” (p. 14)
Anaerobic Energy Sources
ATP-CP (Alactacid) system. Theoretically, this can only sustain work from 7 to 10 seconds. Thus, for efforts of greater duration, performance cannot be as fast as that for very short periods. In efforts that require a greater level of energy, the glycolytic or lactacid system opens up almost immediately to partially preserve the status of the alactacid system. The ATP level remains almost constant in the muscles, but CP drops considerably lower.
Lactacid or glycolytic system. The disadvantage of this system is that it generates lactic acid which accumulates as lactate and H+ ions, causing an increase in cellular and blood acidity. It takes some time before the acidity in the blood balances that in the cells. Because of that time lag, blood samples must be taken some time after work stops to record the highest blood lactate level. In extreme cases, the blood lactate level can reach 25 mM. Work is sustained by this system somewhere between 45 and 60 seconds.
Aerobic Energy Sources
All training and competing in swimming are primarily dependent upon aerobic functioning. The anaerobic systems serve a helping function. They make it possible to commence a performance and sustain it until the aerobic system reaches maximum functioning and takes over as the supplier of energy. In all body movement, part of the energy need will be supplied by anaerobic sources. During work, it is possible for energy from the glycolytic system to be restored, thus, lactate production and removal is balanced. The highest level of that “balancing” is the anaerobic threshold. The intensity of that level can vary greatly but is commonly described as being 4 mM although that is subject to error.
Below the ANThreshold level, the aerobic system needs to not work fully. Above it, there is lactate accumulation. Each condition decreases the maximum functioning of the aerobic system.
“Race results are bettered primarily by moving the lactate/speed curve to the right and not by improving tolerance to higher lactate levels.” (p. 16)
Thus, there is a limit to how much a swimmer should extend him/herself. To exceed a capacity will decrease the volume of training that is possible. To experience a lactate level of 16-20 mM does not lead to much performance improvement. This is because the increases in lactate that occur, happen in such a narrow band of swimming speed that to all intents and purposes training at one lactate level is not that much different to training at the highest level.
“Our experience is that one enters an overtrained state if one trains for a long period of time always at speeds which give 4 mM or more. . . . Classic overtraining results from too much anaerobic work and is characterized by the typical loss of appetite, sleeplessness, loss of weight, etc. The result, as we know, is poorer race performance than should be expected. . . . . The second form of overtraining is called adisonoides overtraining, and reflects increased neurological inhibition. It usually results from too much quantity training at slightly too high a level for too long. This form is often hard to recognize in time to correct. The athlete feels good, trains relatively well, but cannot swim fast in competition.” (p. 17)
“If one wants to improve aerobic capacity it is therefore important not to swim interval series as hard as possible in every workout. In some workouts the intensity should be at the threshold (4 mM). In others it should be just over that (e.g., 5-6 mM) and still in others a little lower (2-3 mM). In this way we avoid the above mentioned overtraining. The body has time to regenerate from the harder endurance training and replenishes the substances which are depleted in training.” (p. 17)
Testing must be repeated every three to four weeks to determine the speeds which correspond to the new level of endurance.