Author(s): BOWEN, M., SAMOZINO, P., MOREL, B., Institution: SAVOIE MONT BLANC UNIVERSITY, Country: FRANCE, Abstract-ID: 2179

INTRODUCTION:
The Critical Power is the severe intensity domain boundary above which fatigue develops drastically and non-steady-state physiological responses occur (1). However, a given power can be developed using different combinations of torque and velocity. During maximal effort, velocity is known to influence the maximal torque or power, which is well described by linear force-velocity or polynomial power-velocity relationships. Although a vast literature has studied critical power, relatively few studies have focused on the effect of the velocity condition. In addition, only 2 velocity conditions were usually tested given the physical hardship and/or time-consuming aspects of assessing critical power using time to exhaustion or 3-min all-out methods (2). Thanks to the development of a new method for assessing critical power during a single 5-min submaximal exercise: the Ramp Above Critical Level Endurance Test (RACLET) (3), the study’s aim was to test the effect of the velocity condition on critical power (Pc) and torque (Tc) over a large spectrum in pedaling.
METHODS:
Based on Bowen model (4), which establishes the proportionality between work accumulation above the critical intensity (Wac) and fatigability during exercise in the severe domain, RACLET was used to determine Tc and Pc under different velocity conditions. Briefly, this test consisted of a 5-min isokinetic pedaling decreasing power ramp, where maximal power was assessed every 30 s from a 6-pedal-strokes sprints. The ramp is designed such that the target power starts above and decreases below Pc without leading to exhaustion. Thus, Pc was determined to be the power target when the maximal capacities stopped decreasing and began to recover. Twenty participants realized five RACLET under different pedaling rate conditions: from 40 to 120, every 20 RPM. From each RACLET, the model was fitted to the maximum power data to obtain the initial power (Pi) & Pc parameters for each cadence. The cadence effect on Tc, Pc, and Wac was modeled and tested using ANOV
RESULTS:
The model’s goodness of fit on the RACLET experimental data (changes in the maximal power over time) was excellent (mean adjusted R²=0.89, RMSE=5%Pi). Tc decreased significantly with the increase in cadence (p<0.001; from 37.3±4.5 to 18.0±4.2 %Ti for 40 to 120 rpm). Furthermore, the Tc as a function of velocity was well described by curved function (median R² = 0.92). The optimal velocity that allows to maximize the Pc was 67.2 ± 19.3 RPM
CONCLUSION:
The results show that it is possible to determine the individual model parameters Tc & Pc, at several velocities using a newly validated submaximal not-to-exhaustion test (RACLET). This allowed us to demonstrate that the critical power was affected by the velocity conditions. The maximum critical power was produced under individual optimum cadence conditions. The velocity condition is crucial when considering and testing the critical power.
1)Burnley. EJAP, 2022
2)Dekerle, JSMS, 2014
3)Bowen, ECSS, 2023
4)Bowen, JTB, 2024