Reliability of a high-intensity cycling capacity test

Objectives: To assess the reliability of the CCT110%, a high-intensity cycling capacity test performed to exhaustion. Design: 27 recreationally active participants (age 23 +/- 4 y; height 1.79 +/- 0.06 m; body mass 78.0 +/- 8.8 kg; Powermax 306 +/- 49W) performed the CCTi in on two occasions. Methods: Performance measures determined from the CCT110% were time to exhaustion (TTE) and total work done (TWD). Blood pH, lactate, bicarbonate and base excess were determined before exercise, immediately after exercise, and 5 min after exercise. Exercise capacity data were analysed using intraclass correlations (ICC), systematic bias ratio, ratio limits of agreement, coefficient of variation (CV) and t-tests. Blood variables were analysed using repeated measures ANOVA and Tukey tests for post hoc comparisons. Results: TTE (mean SD: 134 +/- 20 s and 135 +/- 20 s, P = 0.75) and TVVD (42.2 +/- 10.3 kJ and 42.2 +/- 9.8 kJ, P = 0.97) were not different between trials. The ICC between trials was r = 0.88 for TTE and r = 0.94 for TWD, with the CV being 4.43% for TTE and 4.94% for TWO. There were no between trial differences in blood markers at any time point except immediately post-exercise pH (7.246 +/- 0.041 vs. 7.269 +/- 0.064, P = 0.004). Conclusions: The CCTilo% is a reliable exercise protocol that can be used for nutritional interventions designed to affect intracellular and extracellular pH changes. Although blood pH was significantly different between trials immediately post-exercise, the absolute differences are much smaller than those expected to be seen using nutritional interventions intended to alter extracellular pH during exercise. 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.