The relationship between power and the time to achieve .VO(2max).
OBJECTIVE
The severe exercise intensity domain may be defined as that range of work rates over which .VO(2max) can be elicited during constant-load exercise. The purpose of this study was to help characterize the .VO(2) response within this domain.


METHODS
Eleven participants performed cycle ergometer exercise tests to fatigue at several discrete work rates between 95% and 135% of the maximum power (P(max)) achieved during an incremental exercise test.


RESULTS
As previously demonstrated, the relationship between power and time to fatigue was hyperbolic. The asymptote of power (critical power, P(critical)) was 198 +/- 44 W. The rapidity of the .VO(2) response increased systematically at higher work rates such that the relationship between power and time to .VO(2max) was also well fit by a hyperbola. The power asymptote of this relationship (196 +/- 42 W) was not different from P(critical)(P > 0.05). The two hyperbolic relationships converged at 342 +/- 70 W (136% P(max)).


CONCLUSIONS
These data suggest that, for this population of male and female university students, the upper boundary of the severe exercise intensity domain is approximately 136% P(max). This upper boundary is the highest work rate for which exercise duration is prolonged sufficiently (in this study, 136 +/- 17 s) to allow .VO(2) to rise to its maximal value. The lower boundary for severe exercise is just above P(critical), which is the highest work rate that is sustainable for a prolonged duration and that will not elicit .VO(2max).
Hill
David W
DW
Department of Kinesiology, University of North Texas, Denton, TX 76203-1337, USA. dhill@unt.edu
Poole
David C
DC
Smith
Jimmy C
JC
D000328:Adult; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D013997:Time Factors