Estimate Anaerobic Work Capacity and Critical Power with Constant-Power All-Out Test

Background: The critical power model (CPM) is used extensively in sports to characterize fitness by estimating anaerobic work capacity (W') and critical power (CP). Traditionally, estimates of CP and W' require repeated, time-consuming tests. Alternatively, a 3 min all-out test yields good estimates of W' and CP. However, adoption of the 3 min protocol for regular fitness monitoring is deterred by the mentally/physically strenuous nature of the test. Objective: We propose to examine an alternative single-session testing protocol that can accurately estimate critical power model parameters. Methods: Twenty-eight healthy competitive athletes (cyclists or triathletes) (mean ± SD: age: 38.5 ± 10.4 years, height: 177.9 ± 8.6 cm, mass: 73.4 ± 9.9 kg) participated in 5 sessions on a Lode cycle ergometer in isokinetic mode within a 2-week period. A 3 min all-out test (3MT) was conducted on the first visit to determine CPM parameters from which power outputs for 4 subsequent constant-power plus all-out tests (CPT) were selected to result in exhaustion in 1-10 min. The subjects were to maintain the prescribed power output as consistently as possible at their preferred race cadence. Once the power output could no longer be maintained for more than 10 s, the subjects were instructed to produce an all-out effort. Tests were terminated after power output fell to an asymptote which was sustained for 2 min. Results: The CPM parameters for all of the CPT durations were compared to the traditional CP protocol (significant parameter differences were identified for all CPT durations) and the 3MT (only CPT durations > 3 min were different [3-6 min test, p < 0.01; >6 min test, p < 0.01]). CPT does not estimate traditional CP and W' parameters well. However, the CPT with a duration < 3 min accurately estimates both parameters of a 3MT. Conclusion: Therefore, CPT has the capacity to serve as an alternative tool to assess CP parameters.