Responses during exhaustive exercise at critical power determined from the 3-min all-out test

The purpose of the present study was to examine oxygen consumption rate (V O₂), heart rate (HR), and ratings of perceived exertion (RPE) responses, as well as time to exhaustion (T_lim) values during continuous rides at critical power (CP) determined from the 3-min all-out test. Eighteen participants (mean±s: 23.6±3.5 years; 72.7±18.2 kg) performed an incremental cycle ergometer test to exhaustion to determine peak oxygen consumption rate (V O₂ peak) and HR peak. Critical power was determined from the 3-min all-out test. Metabolic responses (V O₂ and heart rate), RPE, and T_lim were recorded during continuous rides to exhaustion at CP. Linear regression and t-tests were used to compare V O₂, heart rate, and RPE responses during the continuous rides to exhaustion. The T_lim at CP was 12.5±6.5 min. There were significant increases in V O₂, HR, and RPE during the continuous rides at CP and 15 of the 18 participants reached V O₂ peak at exhaustion. Therefore, the V O₂, heart rate, and RPE responses, as well as the T_lim values in the present study suggested that CP determined from the 3-min all-out test overestimated the "true" CP and was within the severe exercise intensity domain.