Muscle power predicts freestyle swimming performance.

The purpose of this study was to determine the relationship between non-invasive laboratory measures of 'muscle power' and swim performance over sprint (50 m) and middle-distance (400 m) events. Twenty-two swimmers performed an upper and lower body Wingate Anaerobic Test (WAT) and a maximal sustained power output test (MPO) for the upper body. Peak power (PP) and mean power (MP) were determined for the WAT, while peak sustained workload (WLpeak) was determined for the MPO. Timed swims over 50 m and 400 m were undertaken by all swimmers during which the number of arm strokes per length was recorded. Highly significant relationships were found between sprint-swim speed (S50) and mean power of the arms (MP(arms)) (r = 0.63, P less than 0.01), between S50 and mean power of the legs (MP(legs)) (r = 0.76, P less than 0.001) and between S50 and the distance covered with each arm stroke (DS) (r = 0.91, P less than 0.001). Multiple regression analyses revealed that WAT power indices for the legs did not significantly increase explained variance in S50 above that of the arms. The relationship between WL(peak) and S400 was highly significant (r = 0.70, P less than 0.001) and indicates the importance of arm power in the longer distance swim events.