The reproducibility of 20-min time-trial performance on a virtual cycling platform

This study aimed to analyse the reproducibility of mean power output during 20-min cycling time-trials, in a remote home-based setting, using the virtual-reality cycling software, Zwift. Forty-four cyclists (11 women, 33 men; 37 ± 8 years old, 180 ± 8 cm, 80.1 ± 13.2 kg) performed 3 x 20-min time-trials on Zwift, using their own setup. Intra-class correlation coefficient (ICC), coefficient of variation (CV) and typical error (TE) were calculated for the overall sample, split into 4 performance groups based on mean relative power output (25 quartiles) and sex. Mean ICC, TE and CV of mean power output between time-trials were 0.97 0.95—0.98, 9.36 W 8.02—11.28 W, and 3.7% 3.2—4.5, respectively. Women and men had similar outcomes (ICC: 0.96 0.89—0.99 vs 0.96 0.92—0.98; TE: 8.30 W 6.25—13.10 vs. 9.72 W 8.20—12.23; CV: 3.8% 2.9—6.1 vs. 3.7% 3.1—4.7, respectively), although cyclists from the first quartile showed a lower CV in comparison to the overall sample (Q1: 2.6% 1.9—4.1 vs. overall: 3.7% 3.2—4.5). Our results indicate that power output during 20-minute cycling time-trials on Zwift are reproducible and provide sports scientists, coaches and athletes, benchmark values for future interventions in a virtual-reality environment