Determining critical power and W′ in running: Accuracy of different two-point models using the power metric

Purpose: This study aims to determine the validity of the critical power (CP) and the work capacity over CP (W) obtained from different twotime trial combinations with respect a five-point model. Method: In a three-week training period, fifteen athletes (age: 23 +/- 5 years; height: 166 +/- 6 cm; body mass: 58 +/- 8 kg; 5 km season-best: 15:29 +/- 00:53 mm:ss) performed five time-trials (i.e., 3, 4, 5, 10, 20 minutes) on a 400 meter track, from which the mean power outputs were obtained through the Stryd Power Meter. An acceptable level of agreement was considered if the following criteria were met: low bias and standard error of the estimate (SEE) (< 14 W [values corresponding to the +/- 5% of the mean CP]; W: < 2.0 kJ [values corresponding to the +/- 10% of the mean W]), R-2 > 0.90, and ICC > 0.81. Results: The CP presented an acceptable SEE for CPwork (1.3 +/- 0.5%) and CP1/time (2.7 +/- 1.1%) when using the five time-trials. For both CP models, the 3-10 minutes was the shortest valid combination, whereas the 3-20, 4-20 and 5-20 minutes showed the greatest level of agreement. The W presented a high SEE for CPwork (14.1 +/- 5.2%) and CP1/time (13.8 +/- 6.2%) when using the five time-trials, therefore, none of the two time-trials combinations were considered. Conclusion: The CP parameter can be accurately estimated from different two time-trial combinations, whereas none reached an acceptable level of accuracy for the determination of W.

Automated summary

This study aims to determine the validity of critical power (CP) and work capacity over CP (W) obtained from different two-time trial combinations in a five-point model. The results indicate that CP can be accurately estimated from different time combinations, but none of the combinations reached an acceptable level of accuracy for determining W.