Laboratory predictors of uphill cycling performance in trained cyclists

This study aimed to assess the relationship between an uphill time-trial (TT) performance and both aerobic and anaerobic parameters obtained from laboratory tests. Fifteen cyclists performed a Wingate anaerobic test, a graded exercise test (GXT) and a field-based 20-min TT with 2.7% mean gradient. After a 5-week non-supervised training period, 10 of them performed a second TT for analysis of pacing reproducibility. Stepwise multiple regressions demonstrated that 91% of TT mean power output variation (Wkg(-1)) could be explained by peak oxygen uptake (mlkg(-1.)min(-1)) and the respiratory compensation point (Wkg(-1)), with standardised beta coefficients of 0.64 and 0.39, respectively. The agreement between mean power output and power at respiratory compensation point showed a bias +/- random error of 16.2 +/- 51.8W or 5.7 +/- 19.7%. One-way repeated-measures analysis of variance revealed a significant effect of the time interval (123.1 +/- 8.7; 97.8 +/- 1.2 and 94.0 +/- 7.2% of mean power output, for epochs 0-2, 2-18 and 18-20min, respectively; P<0.001), characterising a positive pacing profile. This study indicates that an uphill, 20-min TT-type performance is correlated to aerobic physiological GXT variables and that cyclists adopt reproducible pacing strategies when they are tested 5weeks apart (coefficients of variation of 6.3; 1 and 4%, for 0-2, 2-18 and 18-20min, respectively).