Predicting Trail Running Performance With Laboratory Exercise Tests and Field Based Results.

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 VO2 max, 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 (vVO2 max 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, VO2 max 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 (VO2 max, 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%.