The contribution of passive drag as a determinant of swimming performance.

The purpose of the present investigation was to evaluate the contribution of passive drag (Dp) to the prediction of a 400-m swim. A second aim was to evaluate the relation between Dp and some anthropometric factors. In a first experiment, 84 swimmers (both sexes) had their Dp (at 1.4 m.s-1) and VO2max measured in water and put into relation with the performance time of a 400-m swim. Performance times were mainly related to VO2max (r = 0.70 and 0.72, p less than 0.01, for male and female swimmers, respectively). Inclusion of Dp as a second variable improved significantly (p less than 0.01) the accuracy of the regression up to 0.75 and 0.78. Passive drag was also significantly (p less than 0.01) related to height (r = 0.80 and 0.60, p less than 0.01, for male and female swimmers, respectively), weight (r = 0.78 and 0.54, p less than 0.01, for males and females, respectively), and body surface area (r = 0.80 and 0.58, p less than 0.01, for males and females, respectively). In a second group of 7 male swimmers, it was found that Dp values were increased on average by 34% (p less than 0.01) when measured after a maximal expiration as compared to measurements after a maximal inspiration. In a third group of swimmers (n = 41) for which generalized joint laxity was measured, it was found that this variable contributes significantly to the Dp variability. The present results show that Dp can be considered as contributing significantly to prediction of performance in swimming.(ABSTRACT TRUNCATED AT 250 WORDS)