Kinetics of recovery and normalization of running biomechanics following aerobic-based exercise-induced muscle damage in recreational male runners

Objectives: The study aimed to examine the effects of exercise-induced muscle damage on running kinetics. Design: Twenty-six adult recreational male runners performed 60 min of downhill running (− 10 %) at 65 % of maximal heart rate. Running gait changes, systemic and localized muscle damage markers were assessed pre - and post-exercise induced muscle damage protocol. Methods: Running gait was analyzed using a 3D treadmill at baseline, immediately post, 24 h, and 48 h to determine changes in running pressure sway and vertical ground reaction forces. Blood markers, subjective pain perception, and magnetic resonance imaging utilizing T₂ relaxation time of the thigh muscles assessed systemic and localized damage. Linear mixed-effects models examined changes over time. Results: Significant decreases were found in the left leg's first (− 454.0 to − 396.1, P < 0.05) and second (− 532.8 to − 498.2, P < 0.05) VGRF peaks across all time points compared to baseline. The right leg showed reductions in the first vertical ground reaction forced peak at immediately post (− 348.4, P = 0.036) and the second peak at immediately post and 24 h (− 467.4 and − 396.8, P < 0.05). Creatine kinase increased significantly (P < 0.001) at 24 h and 48 h compared to baseline. The anterior thigh muscle compartment showed significant (P < 0.05) increases in mean T₂ values 1 h following exercise protocol remained elevated up to 48 h. Negative correlations were identified between running biomechanics to local and systemic muscle damage markers. Conclusions: Running biomechanics remained impaired for up to 48 h following exercise induced muscle damage and correlated with markers of muscle damage using magnetic resonance imaging.