Oxygen uptake kinetics during incremental- and decremental-ramp cycle ergometry
Date
2011-09
Authors
Rossiter, Harry B.
Ward, Susan A.
Whipp, Brian J.
Journal Title
Journal ISSN
Volume Title
Publisher
Journal Sport Science and Medicine
Abstract
The pulmonary oxygen uptake (VO2) response to incremental-ramp cycle ergometry typically demonstrates lagged-linear first-order kinetics with a slope of similar to 10-11 ml.min(-1).W-1, both above and below the lactate threshold (theta(L)), i.e. there is no discernible VO2 slow component (or "excess" VO2) above theta(L). We were interested in determining whether a reverse ramp profile would yield the same response dynamics. Ten healthy males performed a maximum incremental -ramp (15-30 W.min(-1), depending on fitness). On another day, the work rate (WR) was increased abruptly to the incremental maximum and then decremented at the same rate of 15-30 W. min(-1) (step-decremental ramp). Five subjects also performed a sub-maximal ramp-decremental test from 90% of theta(L). VO2 was determined breath-by-breath from continuous monitoring of respired volumes (turbine) and gas concentrations (mass spectrometer). The incremental-ramp VO2-WR slope was 10.3 +/- 0.7 ml.min(-1).W-1, whereas that of the descending limb of the decremental ramp was 14.2 +/- 1.1 ml.min(-1).W-1 (p < 0.005). The sub-maximal decremental-ramp slope, however, was only 9.8 +/- 0.9 ml.min(-1).W-1: not significantly different from that of the incremental-ramp. This suggests that the VO2 response in the supra-theta(L) domain of incremental-ramp exercise manifest not actual, but pseudo, first-order kinetics.
Description
Keywords
Sport sciences, Oxygen uptake-work rate gain, Incremental-ramp exercise, Decremental-ramp exercise, System linearity, Slow component, Gas-exchange, Heavy exercise, Muscle-fibers, Load exercise, Humans, Fatigue, Tests, Transients, Parameters
Citation
Özyener, F. vd. (2011). "Oxygen uptake kinetics during incremental- and decremental-ramp cycle ergometry". Journal of Sports Science and Medicine, 10(3), 584-589.