Critical power of knee extension exercises does not depend upon maximal strength

Abstract

A possible dependence of critical power (CP) and the Y-intercept of the work/exhaustion time relationship (Y(intercept)) on maximal muscular strength of the same muscle group has been studied in nine endurance-trained subjects, seven gymnasts, and seven weight-lifters. CP was calculated as being equal to the slope of the linear relationship between exhaustion time and the work performed at exhaustion on a knee extension ergometer. Y(intercept) was equal to the intercept between this relationship and the work axis. The muscular strength of the knee was evaluated by measuring the torques exerted on a Biodex knee isokinetic dynamometer at four angular velocities: 0 degrees x s(-1) (T0), 90 degrees x s(-1) (T90), 180 degrees x s(-1) (T180) and 240 degrees x s(-1) (T240). The results of the present study do not support the hypothesis that CP depends upon maximal strength. Indeed, CP was not correlated with T0, T90, T180 or T240 (¿r¿ < 0.01). Y(intercept) was significantly and positively correlated only with T90.