Running-induced fatigue increases coordination variability, regardless of running ability

We examined the effect of fatigue on lower limb coordination variability (CV) and its relationship with running ability. Fifty recreational runners (♀= 25; 18-50 years) ran on a treadmill, at a speed 5% faster than their lactate threshold, until volitional exhaustion. Three-dimensional kinematic data were collected, and CV for sagittal hip-knee and knee-ankle couplings was calculated. One-dimensional repeated measures analysis via Statistical Parametric Mapping (SPM) revealed that CV increased in mid-stance and throughout swing in the final part of the run. Changes in CV were not predicted by VO2peak or 10 km performance, suggesting that the findings are relevant to a range of running populations. These results suggest that trends in CV could inform performance monitoring and represent a real-time proxy of fatigue.