Adaptations to swimming training: influence of training volume

In an effort to assess the contributions of a period of increased training volume on swimming performance, two matched groups of collegiate male swimmers were studied before and during 25 wk of training. For the first 4 wk of this study, the two groups trained together in one session per day for approximately 1.5 h.d-1. During the following 6 wk (weeks 5-11), one group (LONG) trained two sessions per day, 1.5 h in the morning and 1.5 h in the afternoon. The other group (SHORT) continued to train once each day, in the afternoon with the LONG group. Over the final 14 wk of the study, both groups trained together in one session per day (1.5 h.d-1). Although the swimmers experienced significant improvements in swimming power, endurance, and performance throughout the 25 wk study, there were no differences between the groups. However, during the 6 wk period of increased training, the LONG group experienced a decline in sprinting velocity, whereas the SHORT group showed a significant increase in sprinting performance. The test results suggest that a 6 wk period of two 1.5 h training sessions per day does not enhance performance above that experienced with a single training session of 1.5 h each day. It was also noted that both groups showed little change in swimming endurance and power after the first 8 wk of training, though their performances improved significantly after each taper period.