| Abstrakt: |
CARNEVALE, T. J. and G. A. GAESSER. Effects of pedaling speed on the power-duration relationship for high-intensity exercise. Med. Sci. Sports Exerc, Vol. 23, No. 2, pp. 242–246, 1991. Seven males (age = 20.4 ± 0.3 yr) each performed a total of eight exhaustive exercise bouts (four at 60 rpm and four at 100 rpm) in order to determine the influence of pedaling frequency on the parameters of the power-duration relationship for high-intensity cycle ergometry. The power-endurance time data for each subject at each rpm were fit by nonlinear regression to extract parameters of the hyperbolic: (P – PA) · t = W‘, where P = power output, t = time to exhaustion, and PAand W’ are constants. PA(the power asymptote, in watts (W)) reflects an inherent chacteristic of aerobic energy production during exercise, above which only a finite amount of work (W‘, in joules) can be performed, regardless of the rate at which the work is performed. PAat 60 rpm (235 ± 8 W) was significantly (15.9 ± 4.5, P< 0.05) greater than PA100 rpm (204 ± 11 W), thus confirming our hypothesis that endurance would be compromised while cycling at the higher pedaling frequency. In contrast, W’ was not significantly (P> 0.05) affected by cadence (16.8 ± 1.7 kJ at 60 rpm vs 18.9 ± 2.2 kJ at 100 rpm), Our data are consistent with the implications of previous investigations which demonstrated a greater cardiorespiratory and blood/muscle lactate response during constant-power exercise while cycling at high vs low rpm and indicate that the theoretical maximum sustainable power (i.e., PA) during cycle ergometry in untrained males is greater at 60 rpm thin at 100 rpm. |
