The accuracy of simulated indoor time trials utilizing a CompuTrainer and GPS data.

The CompuTrainer is commonly used to measure cycling time trial performance in a laboratory setting. Previous research has demonstrated that the CompuTrainer tends toward underestimating power at higher workloads but provides reliable measures. The extent to which the CompuTrainer is capable of simulating outdoor time trials in a laboratory setting has yet to be examined. The purpose of this study was to examine the validity of replicating an outdoor time trial course indoors by comparing completion times between the actual time trial course and the replicated outdoor time trial course on the CompuTrainer. A global positioning system was used to collect data points along a local outdoor time trial course. Data were then downloaded and converted into a time trial course for the CompuTrainer. Eleven recreational to highly trained cyclists participated in this study. To participate in this study, subjects had to have completed a minimum of 2 of the local Cleves time trial races. Subjects completed 2 simulated indoor time trials on the CompuTrainer. Mean finishing times for the mean indoor performance trial (34.58 ± 8.63 minutes) were significantly slower in relation to the mean outdoor performance time (26.24 ± 3.23 minutes). Cyclists' finish times increased (performance decreased) by 24% on the indoor time trials in relation to the mean outdoor times. There were no significant differences between CompuTrainer trial 1 (34.77 ± 8.54 minutes) and CompuTrainer trial 1 (34.37 ± 8.76 minutes). Because of the significant differences in times between the indoor and outdoor time trials, meaningful comparisons of performance times cannot be made between the two. However, there were no significant differences found between the 2 CompuTrainer trials, and therefore the CompuTrainer can still be recommended for laboratory testing between trials.