Predicting critical power in elite cyclists: questioning validity of the 3-min All-out test

Abstract

Purpose: New applications of the critical power concept, such as the modelling of intermittent work capabilities, are exciting prospects for elite cycling. However, accurate calculation of the required parameters is traditionally time invasive and somewhat impractical. An alternative single test protocol (3-min All-out) has recently been proposed, but validation in an elite population is lacking. The traditional approach for parameter establishment, but with fewer tests, could also prove an acceptable compromise. Methods: Six senior Australian endurance track cycling representatives completed six efforts to exhaustion on two separate days over a three week period. These included 1, 4, 6, 8 and 10 minute self-paced efforts, plus the 3-min All-out protocol. Traditional work versus time calculations of CP and W’ using the five self-paced efforts were compared to calculations from the 3-min All-out protocol. The impact of using just two or three self-paced efforts for traditional CP and W’ estimation were also explored using thresholds of agreement (8W, 2.0kJ respectively). Results: CP estimated from the 3-min All-out approach was significantly higher than from the traditional approach (402±33W, 351±27W, p<0.001), whilst W’ was lower (15.5±3.0kJ, 24.3±4.0kJ, p=0.02). Five different combinations of two or three self-paced efforts led to CP estimates within the threshold of agreement, with only one combination deemed accurate for W’. Conclusions: In elite cyclists the 3-min All-out approach is not suitable to estimate CP when compared to the traditional method. However, reducing the number of tests used in the traditional method lessens testing burden whilst maintaining appropriate parameter accuracy.