LAUSR

PURPOSE Trail running is a complex sport and performance prediction is challenging. Our aim is to evaluate three standard laboratory exercise tests in trail runners and correlate measurements to the race time of a trail competition evaluating its predictive power. METHODS Nine competitive male trail runners (mean age 31±5.8 years) completed three different laboratory exercise tests (step, ramp and trail test) for determination of VO2max, vVO2max, ventilatory and lactate thresholds (LT), mechanical power output and running economy (RE) , followed by a 31km trail race. Runners previously participated in the same race (previous year) and finished in the top 2%. Finishing times (dependent value) were tested in multiple regression analysis with different independent value combinations. RESULTS Linear regression analysis revealed that variables measured during step and ramp test significantly predicted performance. Step test variables (speed at individual anaerobic threshold (IAT) 16.4±1.7 km/h and RE 12km/h (%VO 2 max) 65.6±5.4%) showed the highest performance prediction (R²=0.651; F(2,6)=5.60; P=.043), followed by the ramp test (vVO2max 20.3±1.3km/h; R²= 0.477; F(1,7)=6.39; P=.04) and trail test (Pmax 3.9±0.5 W/kg, VO2max 63.0±4.8 ml O2 .kg-1.min-1, vVT1 11.9±0.7 km/h; R²=0.68; F(3,5)=3.52; P =.11). Adding race time from the preceding year to the step test improved the predictive power of the model (R²=0.988; F(3,5)=66.51; P<.001). CONCLUSION The graded exercise test (VO2max, IAT and RE) most accurately predicted a 31.1km trail running performance. Combining submaximal intensities (IAT and RE) with the previous years race time of that specific event increased the predictive power of the model to 99%.