Critical Power is Related to Cycling Time Trial Performance

The purpose of this study was to evaluate critical power (WCP) as an indicator of aerobic fitness in trained cyclists, and to determine its relationship to cycling time trial (TT) performance. Thirteen competitive USCF category 2 or 3 cyclists provided season's best 40 km TT times (mean [SD]) time = 59.6 min (3.1), and performed two 17 km TT under controlled conditions (26.6 min [1.1]). Ventilatory threshold (VT) and VO₂max were determined from a maximal incremental test. W_CP was calculated using the results of four all-out constant power tests. Mean W_CP was 299 (61) W or 4.1 W x kg^-1, VT was 3616 (750) ml x min^-1 or 49.8 ml x kg^-1 x min^-1 (7.5), and VO₂max was 4596 ml x min^-1 or 63.5 ml x kg^-1 x min^-1 (8.0). W_CP was strongly related to VT and VO₂max, demonstrating that it can serve as a measure of aerobic fitness in this population. Expressions of W_CP were slightly to considerably more highly related to 17 km and 40 km TT performances (r = - 0.77 to - 0.91) than were expressions of VT and VO₂max (r = - 0.71 to - 0.87). It is, concluded that W_CP provides an aerobic fitness measure for competitive cyclists which can be obtained without invasive testing. ln addition, W_CP is strongly related to the TT performance of competitive cyclists.

Key words

Cycling performance - ventilatory threshold - VO₂ max - critical power