INFLUENCE OF CADENCE AND POWER OUTPUT ON CYCLING EFFICIENCY IN TRAINED CYCLISTS AND RUNNERS 1122

Abstract

The goal of this study was to test the hypothesis that trained, experienced cyclists and runners are more efficient at higher cycling cadences. Preferred cadence (PC) was determined in 10 experienced cyclists(VO2max=70.8±4.4 ml/kg/min) and 10 trained runners(72.5±2.2 ml/kg/min) at 3 power outputs (PO; 100, 150, 200 W). Gas exchange was measured on a different day at the same 3 POs and 5 cadences (50, 65, 80, 96, and 110 rpm). Gross (GE) and delta (DE) efficiencies were calculated to determine the influence of cadence and PO on each efficiency measure. PCs of cyclists and runners were similar and did not change appreciably with PO (100 W: 94.7±10.4; 150 W: 94.5±9.7; 200 W: 92.8±7.8 rpm). Cyclists and runners exhibited similar GE at all cadence and PO combinations (p=0.413). For GE there was a significant power x cadence interaction (p<.001) such that as cadence increased GE declined more at 100 W compared to either of the higher POs. Therefore, for GE, cyclists and runners were not more efficient at higher cadences. For DE there was a significant group x cadence interaction (p =.04). In cyclists DE tended to increase with increases in cadence up to 95 rpm, but declined from 95 to 110 rpm, while in runners DE remained relatively unchanged as cadence increased. Cyclists exhibited a higher DE at 95 rpm compared to runners (28.5 vs. 22.9%). Further, the cadence at which DE was maximized (95 rpm) was similar to the PCs of cyclists at each PO. In conclusion cycling experience does not appear to influence GE, but does appear to influence DE. Increases in DE with increasing cadence in cyclists may be due to a specific adaptation, whereby cyclists' leg muscles are contracting closer to the velocity at which muscular efficiency is maximized.