Estimation of critical power with nonlinear and linear models

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Critical power (PC) and anaerobic work capacity (W') are key physiological parameters for understanding exercise tolerance.
• Accurate estimation of PC and W' is crucial for training prescription and performance prediction in athletes.
• Existing models for estimating PC and W' vary, potentially leading to discrepancies in results.

Purpose of the Study:

• To compare the estimates of critical power (PC) and anaerobic work capacity (W') derived from five different mathematical models.
• To assess the agreement and correlation between PC and W' estimates across these models.
• To evaluate the relationship between model-derived PC estimates and the ventilatory threshold for long-term exercise (LTE Tvent).

Main Methods:

• Sixteen healthy males completed exhaustive exercise bouts on a cycle ergometer at various power outputs.
• Data from these exercise bouts were used to calculate PC and W' using five distinct models (two nonlinear, two linear, one exponential).
• Statistical analyses, including correlation coefficients and comparisons of means, were employed to evaluate model agreement.

Main Results:

• All five models demonstrated good data fit (R² = 0.96–1.00).
• Significant differences were observed in PC (195–242 W) and W' (18–58 kJ) estimates among the models.
• PC estimates were highly correlated across models (r = 0.78–0.99), while W' estimates showed moderate to high correlation (r = 0.25–0.95).

Conclusions:

• The choice of model significantly impacts the estimated values of critical power and anaerobic work capacity.
• While PC estimates are generally consistent across models, W' estimates exhibit greater variability.
• Model-derived PC estimates were generally higher than the ventilatory threshold, with varying degrees of correlation.