The Reliability of Performance During Computer-Simulated Varying Gradient Cycling Time Trials

Ergometer based time trials are commonly used to assess performance changes due to training or other interventions. This investigation establishes the reliability of a novel computer simulated cycling time trial. Nineteen cyclists (age: 32 ± 12 years, mass 73 ± 11 kg, height 178 ± 5 cm) completed four time trials over a 20-km course which included numerous changes in gradient. The time trials were completed over a 4-week period in order to establish both short and long-term reliability. Performance time (mean ± SD) for trials one to four was 2265 ± 149 s, 2252 ± 153 s, 2236 ± 146 s and 2240 ± 154 s respectively; the corresponding power output for consecutive trials was 293 ± 35 W, 297 ± 36 W, 299 ± 35 W and 299 ± 35 W. The coefficient of variation (± 90% confidence limits) of performance for trials separated by 7, 14, 21 and 28 days was 1.1% (0.8% – 1.5%), 1.3% (1.1% – 1.9%), 1.3% (1.1% – 1.9%) and 1.5% (1.1% – 2.1%) respectively for time; the corresponding values for power output were 2.0% (1.5% – 2.7%), 2.3% (1.8% – 3.2%), 2.6% (2.0% – 3.6%) and 3.2% (2.5% – 4.5%). Further analysis based on rider ability indicated slower riders were less reliable than faster riders by a factor of ~1.1. Reliability of time trial performance diminishes with increasing time between trials. Additionally, faster riders show better reliability than slower riders over time. Researchers should consider the effect of time between trials and athlete ability when making conclusions about intervention effectiveness.