Reproducibility of the cycling time to exhaustion at VO2 peak in highly trained cyclists

The purpose of the present study was to examine, in highly trained cyclists, the reproducibility of cycling time to exhaustion (Tmax) at the power output equal to that attained at peak oxygen uptake (V̇O 2peak) during a progressive exercise test. Forty-three highly trained male cyclists (M ± SD; age = 25 ± 6 yrs; weight = 75 ± 7 kg; V̇O2peak = 64.8 ± 5.2 ml·kg -1·min-1) performed two Tmax tests one week apart. While the two measures of Tmax were strongly related (r = 0.884; p < 0.001), Tmax from the second test (245 ± 57 s) was significantly higher than that of the first (237 ± 57 s; p = 0.047; two-tailed). Within-subject variability in the present study was calculated to be 6 ± 6%, which was lower than that previously reported for T max in sub-elite runners (25%). The mean Tmax was significantly (p < 0.05) related to both the second ventilatory turnpoint (VT2; r = 0.38) and to V̇O2peak (r = 0.34). Despite a relatively low within-subject coefficient of variation, these data demonstrate that the second score in a series of two Tmax tests may be significantly greater than the first. Moreover, the present data show that Tmax in highly trained cyclists is moderately related to VT 2 and V̇O2peak.