The influence of flywheel weight and pedalling frequency on the biomechanics and physiological responses to bicycle exercisef

The physiological, subjective and biomechanical effects of altering flywheel weight and pedalling rate on a Quinton Model 870 bicycle ergometer were studied. Steel plates were added to the flywheel to increase its weight to 35 9 kg with a moment of inertia of 1 65 kg m¹. A 1-5 kg spoked wheel with a moment of inertia of 01 kgm¹ was used as the light flywheel. Eight subjects pedalled on two separate occasions for 6min at 40, 50, 60, 70, 80 and 90r.pjn. with workload levels representing 30 and 60% of their VOjinax with each flywheel. Force plate pedals were used to measure the total resultant force on the pedals (F*) and the component perpendicular to the crank arm (F_r). A force effectiveness index (FEI) was defined as the average of F_X/F_H over a crank cycle. The result showed no statistically significant change (p <005) in P'O j, heart rate and rating of perceived exertion of the FEI as a function of flywheel weight except for the VO, at 50 r.pjn. for the light workload. As the r.p.m. increased from 40 to 90r.pjn., the FEI decreased from 05 to 035 with the heavy load and from 036 to 0-22 with the light load. Measured physiological, subjective and biomechanical indices did not change significantly with flywheel weight. Increasing the pedalling rate caused a significantly less effective application of forces to the crank arm with only a small change in &0₂.