Also known as anaerobic glycolysis, involves the process of glucose converting to lactic acid. ATP recycling during this period is much slower than the previously described ATP-CP system, this will mean that once this anaerobic metabolism becomes the main energy source athletes will be unable to maintain maximum speed. Anaerobic Metabolism, during Intense Swimming, occurs almost immediately, however, it does not become the main contributor of energy until the ATP-CP system depletes. Both anaerobic metabolism and ATP-CP energy source are both equal from approximately 3 to 10 secs of maximum effort. Thereafter, the creatine phosphate-ATP recycling ceases and anaerobic metabolism becomes the primary energy source – usually for the last 20 secs of maximum effort. During this transition, there is a decline in the swimmers power of approximately 10% (Newsholme etal. 1992).
Training Anaerobic Metabolism
Training does appear to increase both the quantity and activity of enzymes of anaerobic glycolysis (Costill, Fink, and Pollock 1976; Costill 1978; Jacobs et al. 1987). However, there is a contradiction to this. Sprint training provides an ideal platform to bring about improvements anaerobically, endurance training, on the other hand, seems to hinder this effect. This is the hardest hurdle to tackle when considering this form of training as many swimmers strive to improve both their endurance base and speed, however, the former seems to reduce the rate of anaerobic metabolism. It has been suggested that the anaerobic system is at it’s optimum when athletes are untrained – evidence cited from the fact many swimmers experience their best sprint performances after long breaks.
Other than those training solely for 50m events, all that swimmers training for greater lengths can hope for is to maintain their innate level of providing energy from anaerobic metabolism, although, large volumes of endurance work will most likely decline the swimmers level of anaerobic metabolism.
Taper may allow middle distance and distance swimmers to counter this effect, although, this may not be long enough and the swimmers innate ability may not return until endurance training has been significantly reduced or ceased for several weeks. Swimmers who have seen great improvements in their endurance, may see good performances despite the loss in speed. Sprinters on the other hand will not produce a good result if they cannot regain their speed.
In conclusion, anaerobic metabolism influences a swimmers speed more significantly than ATP-CP system, which only accounts for the first few seconds in a race. Developing a swimmers anaerobic ability should not be seen as a high priority in athletes who train for events greater than 50m as endurance training hinders and may even cause a decline in anaerobic metabolism, although, sprint training may maintain the swimmers innate ability. Sprinters must take great care in the volume of endurance training they do as it can take very long periods for a swimmer to regain his/hers innate ability. It could be argued that a sprinter’s training would be more effective if it had a greater focus toward improving muscular contraction and anaerobic metabolism rather than improving any aerobic capacity; if any at all.
Yours in Swimming,