Pedalling Cadence Affects V̇o2 Kinetics in Severe-Intensity Exercise.

The purpose was to investigate the effects of pedalling cadence on V̇o2 kinetics in severe-intensity cycling exercise. This question is pertinent to exercise testing, where cadence is an important (and often confounding) variable, and to performance, where V̇o2 kinetics determines the initial reliance upon anaerobic reserves. Eighteen university students performed tests to exhaustion at 241 ± 31 W, using cadences of 60, 80, and 100 rev·min-1. V̇o2 data were fitted to a 2-component model (primary phase + slow component). Responses during the 3 tests were compared using a repeated-measures analysis of variance, with significance at p < 0.05. The mean response time of the primary phase of the V̇o2 response (time to reach 63% of the response) was progressively smaller (response was faster) at higher cadences (37 ± 4 seconds at 60 rev·min-1, 32 ± 5 seconds at 80 rev·min-1, 27 ± 4 seconds at 100 rev·min-1), and there was a concomitantly faster heart rate response. In addition, the time delay before the slow component was shorter, the amplitude of the primary phase was greater, and the amplitude of the slow component was smaller at the higher cadence. The results suggest that pedalling cadence itself-and not just the higher metabolic demand associated with higher cadences-may be responsible for differences in temporal characteristics (time delays, time constants) of the primary and slow phases of the V̇o2 response. Exercise scientists must consider, and coaches might apply, the relationship between V̇o2 kinetics and pedalling cadence during exercise testing. [ABSTRACT FROM AUTHOR]