Surface-related differences in lower-limb biomechanics during running on concrete and artificial turf using OpenSim.

Surface-related alterations in joint loading during trail running remain unclear. Twenty male recreational rearfoot-strike runners performed overground running at 3.3 m/s on concrete and artificial turf. Three-dimensional kinematics, ground reaction forces (GRFs), and surface electromyography (sEMG) were recorded. An OpenSim Gait2392 model combined with Static Optimisation and Joint Reaction Analysis was used to estimate ankle, knee, and hip joint reaction forces (JRFs). Vertical and anteroposterior GRFs and vertical JRF peaks showed no significant differences between surfaces. However, the concrete surface yielded larger mediolateral GRF magnitudes (p < 0.001) and higher peak anterior ankle JRF (p = 0.049). Exploratory analyses indicated potential differences in knee and ankle mechanics, but these did not survive false discovery rate correction. Under speed-controlled running conditions, surface type had limited effects on vertical GRF and proximal joint loading. Adaptations to different surfaces appear to occur mainly through distal mechanical adjustments, particularly at the ankle and in mediolateral force control.  .