Reliability of sprint test indices in well-trained cyclists

The study aim was to assess reliability of repeated laboratory sprint tests in well-trained endurance cyclists. Eleven male cyclists (mean standard deviation: 27 6 yr, 1.79 +/- 0.04 m, 70.1 +/- 3.3 kg) performed a maximal 30-second sprint test on four separate occasions using their own bicycle fitted with an SRM powermeter on a Kingcycle air-braked ergometer. Peak power Output (W-peak), mean power N-mean) and an index of fatigue (FI) were calculated. Three minutes post sprint, capillarised blood lactate measurements were taken and analysed. No significant differences (p > 0.05) were found between trials for W-peak, W-mean, FI and blood lactate concentration. Repeatability of Wpeak, Wmean, and fatigue index improved across trials 2 and 3 when compared to trials 1 and 2. The highest CV for these variables was recorded between trials 3 and 4. The CV for W-peak was 4.5 +/- 1.6%, W-mean 2.4 +/- 1.2%, and FI 17.2 +/- 7.1%. Intraclass reliability coefficients were 0.93 (95% CI 0.84 - 0.98), 0.94 (95% CI 0.86 - 0.98) and 0.89 (95% CI 0.69-0.95) respectively. Blood lactate concentration ranged between 5.35 and 14.52 mmol.l(-1), with a mean CV of 12.1 +/- 4.2 %. The CV for trials 2 and 3 revealed the highest CV for blood lactate concentration (15.1%). The lowest CV for this variable (10.2%) was recorded between trials 3 and 4. The intraclass reliability coefficient for blood lactate concentration was 0.79 (95 % CI 0.58-0.93). The results of this study indicate that there is no improvement in the reliability of sprint test indices when assessing well-trained, experienced cyclists, riding on their own cycle equipment.