Validity of critical velocity as swimming fatigue threshold in the competitive swimmer.
The purpose of this investigation was to determine whether the critical velocity (CV) as the swimming speed which can be theoretically maintained for a very long time without exhaustion could be applied to estimate the swimmer's endurance performance. CV was based on the concept of critical power originality established by Monod and Scherrer (1965) and extended by Moritani et al. (1981), and expressed as the slope of a regression line between swimming distance (D) at each velocity and its sustained time (T). Seventeen highly trained swimmers were instructed to swim the four different swimming distances (50 m, 100 m, 200 m and 400 m) at maximal effort using the swimming pool. In the results of CV, the regression relations between D and T were expressed in the general form, D = a + bxT, with r2 showing higher than 0.997 (p less than 0.001). These results indicate extremely good lineality. Furthermore, VO2max during incremental exercise test, swimming speed corresponding 4 mM of blood lactate concentration (V-OBLA) and mean velocity in the 200 m and 400 m freestyle (V-200 and V-400) were measured on nine subjects. Significant correlations were found between CV and V-OBLA (r = 0.862, p less than 0.01), CV and V-200 (r = 0.781, p less than 0.01), CV and V-400 (r = 0.999, p less than 0.001), V-OBLA and V-400 (r = 0.869, p less than 0.01) and V-200 and V-400 (r = 0.776, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)