Mechanomyographic and metabolic responses during continuous cycle ergometry at critical power from the 3-min all-out test

There are limited data regarding metabolic responses during continuous exhaustive rides at critical power (CP) from the 3-min all-out test. In addition, no previous studies have examined the mechanomyographic (MMG) responses at CP from the 3-min all-out test. Therefore, this study examined the metabolic and MMG responses during continuous exercise at CP determined from the 3-min all-out test. Nine college-aged females (mean. ±. SD: age 23.0. ±. 3.6. yrs) performed an incremental test to exhaustion on a cycle ergometer to identify the gas exchange threshold, peak oxygen consumption rate (V̇O2 peak) and heart rate peak (HR peak). The V̇O2, HR, MMG amplitude and mean power frequency (MPF) responses were examined during continuous rides to exhaustion at CP (81. ±. 6% peak power). There were significant increases in V̇O2 and HR over time and there was no significant difference between V̇O2 peak and V̇O2 at exhaustion or HR peak and HR at exhaustion. There were, however, no significant changes for MMG amplitude or MPF over time. Therefore, the current findings suggested that the 3-min all-out test overestimated CP and the demarcation between the heavy and severe intensity domains. Specifically, the V̇O2 and HR responses did not reach a steady state and were driven to peak values. Furthermore, the non-significant change in MMG amplitude and MPF were consistent with the responses observed at fatiguing power outputs (i.e., >80% peak power).