Abstract
The power‐duration relationship accurately predicts exercise tolerance for constant power exercise performed in the severe intensity domain. However, the accuracy of the prediction of time to task failure (T lim) is currently unclear for work rates (WR) above severe intensities; that is, within the extreme intensity domain (T lim < 2 min). We hypothesized that T lim would be shorter for WRs within the extreme intensity domain than predicted from the linear 1/time relationship of the severe intensity domain which would suggest mechanisms limiting exercise are different between intensity domains. Six men completed 7 knee‐extension tests. T lim of extreme intensity exercise (60%, 70%, 80%, and 90% 1RM; T lim < 2 min) were compared to the predicted T lim from the slope of the S1–S3 (T lim ≥ 2–15 min) regression. Twitch force (Q tw) and maximal voluntary contraction (MVC) were measured on the right vastus lateralis before and after each test. T lim at 70–90% 1RM were shorter than the T lim predicted by the severe domain 1/time model (P < 0.05); however, T lim at 60% 1RM was not different than the predicted severe T lim, suggesting the mechanisms limiting extreme exercise manifest ≥60% 1RM. A significant linear relationship for 60–90% 1RM was observed which suggested a curvature constant unique to the extreme domain (Wext′) that was smaller than the W ′ of the severe domain (1.5 ± 0.6 vs. 5.9 ± 1.5 kJ, P < 0.001). Q tw and MVC were significantly decreased following severe exercise, however, Q tw and MVC were not significantly decreased following 80% and 90% 1RM, giving evidence that mechanisms causing task failure were recovered by the time post‐exercise measurements were made (~90 sec).
Highlights
Background and AimThe power-duration relationship accurately predicts exercise tolerance for constant power exercise performed in the severe intensity domain
maximal voluntary contraction (MVC) was determined as the greatest force attained prior to the superimposed muscle doublet stimulation
A two-way ANOVA with repeated measures was used to test for differences in time of contraction using EMG burst length time across all work rates and between the average of the first 5 contractions compared to the average of the last 5 contractions (Intensity & First/Last)
Summary
These data suggest that exercise tolerance in the extreme domain is limited by different factors than in the severe domain. There is a separate but measurable W’ext. The factors limiting exercise in the extreme domain must be those from can be recovered by the time post-exercise measurements were made
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have