Effects of 10min vs. 20min passive rest after warm-up on 100m freestyle time-trial performance: A randomized crossover study.

OBJECTIVES

The aim of this study was to compare the effect of 10min vs. 20min passive rest post warm-up on performance in a 100m freestyle time-trial.

DESIGN

Randomized crossover.

METHODS

Eleven competitive male swimmers performed two experimental trials on different days, consisting of 100m freestyle time-trials following 10min or 20min passive rest after a standard 1200m warm-up. Performance (time-trial), biomechanical (stroke length, stroke frequency, stroke index, propelling efficiency), physiological (blood lactate concentrations, heart rate, core and tympanic temperature), and psychophysiological (perceived effort) variables were assessed during both trials.

RESULTS

Time-trial performance was faster after 10min as opposed to 20min passive rest (58.41±1.99s vs. 59.06±1.86, p<0.01). This was supported by strong effect sizes (d=0.99) and the qualitative indication of "likely" positive effects. Heart rate before the time-trial was also higher after 10min passive rest (89±12bpm vs. 82±13bpm; p<0.01). Furthermore, net core temperature and oxygen uptake values before the time-trial were substantially lower after 20min passive rest.

CONCLUSIONS

These data suggest that the 10min post warm-up passive rest enhances 100m freestyle performance when compared to a 20min period. An improvement that appears to be mediated by the combined effects of a shorter post warm-up period on core temperature, heart rate and oxygen uptake.