Physiological factors determining downhill vs uphill running endurance performance

AbstractObjectives Recent studies investigated the determinants of trail running performance (i.e., combining uphill (UR) and downhill sections (DR)), while possible specific physiological factors specifically determining UR vs DR performances isolating DR) remain presently unknown. This study aims to determine cardiorespiratory responses outdoor time-trial explore in highly trained runners. Design Randomized controlled trial. Methods Ten male highly-trained endurance athletes completed 5-km time-trials (average grade: ±8%) were tested for maximal oxygen uptake, lower limb extensor strength, local muscle endurance, leg musculotendinous stiffness, vertical jump ability, explosivity/agility sprint velocity. Predictors using correlation commonality regression analyses. Results Running velocity was higher (20.4±1.0 12.0±0.5km·h−1, p<0.05) with similar average heart rate (95±2% 94±2% rate; p>0.05) despite V̇O2 (85±8% 89±7% V̇O2max; p<0.05). Velocity at V̇O2max (vV̇O2max) body mass index (BMI) strength significant predictors (r2=0.94) whereas vV̇O2max, stiffness (r2=0.84). Conclusions Five-km are both well explained by three independent predictors. If two shared between (vV̇O2max strength), their relative contribution is different and, importantly, third predictor appears very exercise modality (BMI DR).