Power Profile of Olympic Cross-Country Mountain Biking: Durability Matters.

Inoue, A, Mateo-March, M, Protzen, G, do Carmo, EC, Lattari, E, Costa, VP, and Bezerra da Silva, E. Power profile of Olympic cross-country mountain biking: Durability matters. J Strength Cond Res XX(X): 000-000, 2026-Power output decline may represent an important indicator of durability in Olympic cross-country mountain biking (XCO-MTB), highlighting the need to evaluate performance when fatigued. This study aimed to (a) assess the impact of a fatigue protocol on the power profile of XCO-MTB athletes and (b) explore how power profile and durability interact to shape performance. Twenty-five male XCO-MTB athletes underwent power profile tests in randomized "fresh" and fatigued conditions, separated by 48 hours. In the fatigued condition, the power profile test was immediately preceded by a 140-minute fatigue protocol that included 5 repeated 8-minute efforts at 105-110% of critical power. After 72 hours, athletes completed an individual time trial on an XCO-MTB track and were classified as high performance (HP, n = 9) or low performance (LP, n = 9) based on their time trial results; the middle tertile (n = 7) was excluded for clearer differentiation. Power output across all durations (5 seconds-10 minutes) and total work (kJ and kJ kg-1) were significantly lower in the fatigued condition compared with the "fresh" condition (p < 0.05 to p < 0.0001, small-to-large effect sizes, Hedges' g = 0.32-1.52). Both groups experienced percentage reductions in power output, but the LP group showed significantly greater declines (≈14-20%, p < 0.05 to p < 0.01, moderate-to-large effect sizes, Hedges' g = 0.93-1.88) than the HP group (≈4-8%), except at the 15-second duration. In conclusion, fatigue significantly impairs the power profile of XCO-MTB athletes, whereas higher-performing athletes demonstrate greater durability through smaller declines in power output across effort durations under fatigued conditions.