Reproducibility of a laboratory based 20-km time trial evaluation in competitive cyclists using the velotron pro ergometer

The purpose of this study was to evaluate the reliability of a 20-km cycling time trial using the Velotron cycle ergometer in competitive cyclists. Twenty male cyclists (VO2max = 68.5 +/- 3.6ml center dot kg(-1) min(-1); peak power (P-peak) = 469 +/- 33 W) participated in this study. Each subject performed a VO2max test and 3 separate 20-km time trials (TT1, TT2, and TT3). Data from trials were compared using a one-way ANOVA. Coefficients of variation (CV) and 95% confidence intervals (CI) were calculated between trials. Values are mean +/- SD unless otherwise noted. Performance time T-tot (30.03 +/- 1.24, 30.12 +/- 1.21, and 30.14 +/- 1.21 min) and mean absolute power (P-mean) (326 +/- 35, 323 +/- 35, 322 +/- 34 Watts) were not significantly different across TT1-TT3. P-mean was highly related between TT1-TT2 (r = 0.96; p < 0.01) and TT2-TT3 (r = 0.97; p < 0.01). A low CV was also demonstrated between trials for P-mean (TT1-TT2 = 2.1 %, Cl = 1.6 % to 3.1 %; TT2-TT3 = 1.9%, Cl = 1.4% to 2.8%). P-peak and P-mean were both correlated to T-tot in TT1 with P-mean accounting for most of the variance in T-tot (R-2 = 0.993). These data show that performance in a 20-km time trial using the Velotron ergometer is highly reproducible in competitive cyclists. Furthermore, the CV variance demonstrated between trials is comparable to that expected during actual performance in elite athletes.