Reliability of Time to Exhaustion Above the Power Output at VO 2peak in Trained Mountain Bikers.

To our knowledge, no study has investigated the reliability of the time to exhaustion (TTE) test during constant-load trials in Olympic distance cross-country mountain bike (XCO-MTB) athletes. Thus, the aim was to analyze the reliability of the TTE test at intensities above peak oxygen uptake (VO2peak ) in trained XCO-MTB athletes. Fifteen male XCO-MTB athletes (mean ± SD: age 31.5 ± 6.6 years, stature 174.0 ± 5.4 cm, body mass 67.2 ± 5.1 kg, VO2peak 64.5 ± 4.7 mL·kg-1 ·min-1 ) completed 2 TTE tests on the cycle ergometer with 4 different intensities above the maximal work rate in the incremental test (Wmax ) (105%, 120%, 130%, and 140% of Wmax ). There was moderate reliability between TTE tests at 105% (intraclass correlation coefficient (ICC) = 0.81, p ≤ 0.001; coefficient of variation (CV) = 9.1%; standard error of measurement (SEM) = 18.3%), and 120% (ICC = 0.88, p ≤ 0.001; CV = 6.6%; SEM = 9.3%) Wmax . For intensities of 130% (ICC = 0.53, p = 0.018; CV = 9.2%; SEM = 15.8%) and 140% (ICC = 0.56, p = 0.012; CV = 12.2%; SEM = 13.5%) Wmax , the reliability results proved to be questionable. In addition, no significant differences were found between the 2 TTE tests in all intensities ( p > 0.05). Caution should be taken when assessing TTE above VO2peak or when using it as a performance indicator, given its moderate to questionable reliability.