This study investigated the correlation between cycling economy (CE) and gross efficiency (GE) in Olympic cross-country mountain biking (XCO-MTB) race performance. Also was examined the correlation between CE, GE, and peak oxygen uptake (VO2peak). Sixteen male XCO-MTB athletes (30.9 ± 5.2 years, 68.7 ± 5.6 kg, 175.0 ± 5.7 cm, and VO2peak: 65.4 ± 4.9 mL·kg-1 min-1) completed two experimental sessions. On the first, anthropometric assessments and a maximal incremental test were performed. The maximal incremental test was performed in the cycle ergometer to determine VO2peak, CE, and GE. A week later, an XCO-MTB race was performed in the second visit, where the official race time was used as a performance indicator. An inverse, significant moderate correlation was found between race time (8318.3 ± 459.0 s) and both CE (r = -0.53; CI95% = -0.84 to -0.10; p = 0.0008), and GE (r = -0.67; CI95% = -0.89 to -0.22; p = 0.0001). However, the moderate correlation between CE and race time showed low power. No significant correlation was found between VO2peak and either CE (r = -0.45; CI95% = -0.77-0.06; p = 0.08) or GE (r = -0.47; CI95% = -0.78-0.04; p = 0.07). In conclusion, gross efficiency is an important component of XCO-MTB race performance. The VO2peak was not related to CE and GE. The evaluation of GE may be a useful addition to the battery of physiological tests in mountain bikers.Highlights The gross efficiency can be a performance indicator related to the Olympic cross-country mountain biking race;The cycling economy has a moderate association with race time, but its use as a measure related to Olympic cross-country mountain biking race performance should be carried out with caution;Despite VO2peak's influence on both cycling economy and gross efficiency measures, our results do not show a relationship with Olympic cross-country mountain biking athletes.
Keywords: Assessment; efficiency; off-road cycling.