Fatigue Index vs Peak Power as an Accurate Predictor of Mountain Biking Performance in High School Mountain Bike Athletes

Abstract

There are limited data examining the association between laboratory test performance and mountain biking race performance. The Ryan Wingate (WIN) anaerobic cycling test is used to determine anaerobic power or Fatigue Index (FI), which is defined as the % decline in power output during a 30 second trial, in addition to other variables such as Peak Power (PP) output. PURPOSE: The purpose of this research was to determine the correlation (if any) between PP and FI in MTB athletes and race/lap time. METHODS: 28 MTB athletes (age: 16.5 ± 1.5 years; body weight: 66 ± 8.1 kg; height: 167.64 ± 8.12 cm) from the a local high-school mountain biking team completed one round of Wingate (WIN) testing prior to their first racing event of the season. Individual race times were collected from the first race of the season at http://www.nationalmtb.org. Based on interpretation of the data, a Spearman’s correlation was used to determine the relationship between participant’s average lap time during a mountain bike race and FI and a Pearson’s correlation was used to determine the relationship between participant’s average lap time during a mountain bike race and PP. RESULTS: There was a moderate, positive monotonic correlation between average lap time and FI (ρ =0 .55, n = 28, p-value < 0 .01) and there was no significant correlation between PP during a WIN test and race performance measured in average lap time (t26=0.8047, p-value=0.4283). DISCUSSION/CONCLUSION: These results suggest that the FI gathered from a single 30 second WIN test may be a more accurate method for predicting race performance or potential for success in MTB riders aged 14-18 than PP. These results also indicate that coaches and adolescent mountain bike athletes should focus on training strategies that target improvements in anaerobic power or FI (i.e., interval training).