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-θPA) · t = W′, where P = power output, t = time to exhaustion, and θPa and W′ are constants. θPa (the power asymptote, in watts (W)) reflects an inherent characteristic 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. θpA at 60 rpm (235 ± 8 W) was significantly (15.9 ± 4.5%, P < 0.05) greater than θPa at 100 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., θPa) during cycle ergometry in untrained males is greater at 60 rpm than at 100 rpm.
- Muscular work
- Oxygen uptake
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation