Costill, D. L., Thomas, R., Robergs, R. A., Pascoe, D., Lambert, C., Barr, S., & Fink, W. J. (1991). Adaptations to swimming training: influence of training volume. Medicine and Science in Sports and Exercise, 23, 371-377.

An attempt was made to assess the contributions of increased training volumes on swimming performance. Two matched groups of college male swimmers were studied before and during a 25-week training period. One group practiced one and a half hours a day. The other practiced once a day for weeks 1 through 4, twice a day each for one and half hours for weeks 5 through 11, and once a day for the remaining 14 weeks. Stroke length, heart rate, long and short swim performances, and various blood parameters were measured periodically.

Over the 25-week period there were no differences between the groups. However, during the increased period of training, the extra-loaded group exhibited a decrease in sprinting velocity while the other increased. Both groups showed little change in swimming endurance and power after the first eight weeks of training, although performances did change after two taper (rest) periods.

The need for extensive training to maximize conditioning and enhance swimming performance was not supported. Extra training did not produce any benefits that were different to those attained in once a day training. Actually, increased training was associated with no improvements in swimming power and a decline in swimming velocity. The loss of muscular strength with intense training recovered after a few days or weeks of reduced training (particularly in the taper).

Implications. The changes in endurance that occurred in the first eight weeks were independent of the training load (they were similar for both groups). From then on, there was no appreciable change in endurance fitness. One has to question the value of excessive training for sprinters if speed is reduced as was demonstrated in this study.

These findings may not be applicable to male age-group (<16 yrs) or female swimmers. In considering the lack of demonstrated effects that are generally attributed to increased training by coaches the authors suggest:

". . . our knowledge of the need for specificity in training might lead us to assume that such training may not provide the adaptations needed for optimal swimming performance. Since the majority of the competitive swimming events last less than 3 min, it is difficult to understand how training at speeds that are markedly slower than competitive pace for 3-4 hr/day will prepare the swimmer for the supramaximal efforts of competition." (p. 376)

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