EFFECT OF CRANK ARM LENGTH AND PEDALLING RATE ON ENERGY EXPENDITURE DURING STEADY-RATE CYCLING 1503:

The primary purpose of this investigation was to determine the interaction effect of selected crank arm length and pedalling rate combinations on energy expenditure when cycling at a constant work rate. A secondary purpose was to examine the correlation between the crank arm length (CAL) allowing the lowest oxygen consumption (optimum CAL) and leg length measurement. Seven male competitive cyclists, ages 21 to 34 years, completed six, 15-minute test protocols riding their personal bicycles on a stationary trainer at a constant average workload of 250 watts. The six test protocols included combinations of three crank arm lengths (165, 172.5, 180 mm) and two pedalling rates (60, 90 rpm). Oxygen consumption and heart rate were determined every 20 seconds of each work bout. A three-by-two factorial ANOVA with repeated measures revealed a significant crank arm length by pedalling rate interaction effect (p