The effect of fatigue on the ankle and knee kinematics and kinetics in moderately and highly trained healthy non-rearfoot runners.

The aim of this study was to compare selected ankle and knee kinematic and kinetic parameters before and a fter a prolonged exhaustive treadmill run between two groups of non-rearfoot footstrike pattern (NRFP) runners with different training volumes. Twenty-eight habitual NRFP runners were assigned to two groups based on their weekly training volume (Highly-trained (HT)/Moderately-trained (MT)). Participants underwent the VO2max test, and the exhaustive treadmill ran with biomechanical analysis at the beginning and the end. The two-way RMANOVA was used to assess differences between the groups and the phase of the run. A paired t-test was used for post-hoc analysis in case of significant interaction effect. Kinetic results showed significant group effect for ankle plantarflexion moment and hip external rotation moment (end-phase: both greater in MT group). Kinematic results showed significant group×phase interaction for ankle dorsiflexion angle (end-phase: greater in MT group) at initial contact (IC), peak knee flexion angle (end-phase: greater in MT group), and peak ankle eversion angle during the stance phase (end-phase: greater in HT group). Additionally, a group effect was found for knee flexion angle at IC (end-phase: greater in HT group). This study suggests that HT healthy NRFP runners may have less potential for increased biomechanical risk of AT overload during an exhaustive run.