The laboratory assessment of endurance performance in cyclists.

Performance in endurance activities depends on maximal aerobic capacity (VO2max) and the ability to sustain a high percentage of VO2max over time. This study examined whether noninvasive laboratory measures would be valid predictors of endurance performance in an individual-start bicycle race (TT). Eight experienced male cyclists (age = 25.1 +/- 3.3 years, weight = 75.0 +/- 5.7 kg, VO2max = 5.05 +/- 0.4 L.min-1) performed a progressive incremental exercise test to exhaustion on a cycle ergometer. VO2max, maximum power output, and ventilatory threshold were determined. Later the subjects completed a 40-km TT. Power output at the ventilatory threshold (VT watts) was correlated with race performance time and calculated power output during the competition (r = -0.81; r = 0.82). VT watts and VO2max accounted for 75% of the variance between subjects (r = 0.91) in performance time. These data indicate that simple laboratory measures can predict TT performance in trained cyclists. Individual differences may be accounted for by motivation, aerodynamic position, and efficiency.