Purpose: The purposes of this study were to re-examine the findings of previous studies by comparing the critical power (CP) estimates from five mathematical models and to determine the time to exhaustion during cycle ergometry at the lowest CP estimate from the five models.
Methods: Nine adult males performed a maximal incremental test to determine peak power and five or six randomly ordered trials on a cycle ergometer for the estimation of CP. Two linear, two nonlinear, and one exponential mathematical model were used to estimate CP. The subjects then completed two trials to exhaustion, or 60 min, at their lowest estimate of CP from the five models.
Results: The nonlinear three-parameter model (Nonlinear-3) produced a mean CP that was significantly (P < 0.05) less than the mean CP values derived from the other four models and was the lowest CP estimate for each subject. Two and three subjects, however, did not complete 60 min of cycling during the first and second trials at CP, respectively. At the end of the trials the subjects who completed 60 min of cycling had a mean heart rate of 92% of their maximum and a mean rating of perceived exertion of 17.
Conclusion: These findings support previous studies that have indicated that in many cases CP overestimates the power output that can be maintained for at least 60 min.