Abstract Background: While gait retraining and neuromuscular strengthening demonstrate individual clinical efficacy in medial tibial stress syndrome (MTSS) management, the integrated biomechanical mechanisms through which combined intervention modifies lower limb loading parameters and tissue stress remains inadequately characterized in contemporary literature. High-resolution biomechanical quantification integrating three-dimensional motion capture, ground reaction force analysis, electromyography, and musculoskeletal modelingremains sparse in MTSS research despite its importance for mechanistic understanding and intervention optimization. Objective: To comprehensively characterize the biomechanical adaptations resulting from combined gait retraining and targeted neuromuscular strengthening through multimodal analysis including three-dimensional kinematics, ground reaction forces, muscle activation patterns, and finite element modeling of tibial stress distribution in participants with MTSS. Methods: Sixty-four participants (18-45 years) with clinically and radiologically confirmed MTSS received 12 weeks of combined gait retraining and neuromuscular strengthening intervention. Comprehensive biomechanical assessment occurred at baseline, 6 weeks, 12 weeks, and 6-month follow-up utilizing synchronized three-dimensional motion capture (12-camera Vicon system, 250 Hz sampling), force plate analysis (dual AMTI force plates), and intramuscular/surface electromyography (EMG) of tibialis posterior, soleus, gastrocnemius, and tibialis anterior. Peak tibial acceleration was measured via accelerometer positioned at the distal anteromedial tibia. Musculoskeletal modeling (OpenSim) calculated muscle forces and joint reaction forces; finite element analysis quantified tibial stress distribution. Primary outcomes included changes in peak tibial acceleration, loading rate, and medial tibial stress. Secondary outcomes encompassed muscle activation timing patterns, joint kinematics, and sustainability of adaptations post-intervention. Results: Combined intervention produced significant peak tibial acceleration reduction (baseline 11.4±1.8g to 12-week 8.2±1.4g; 28.1% reduction; p<0.001; Cohen's d=1.94). Loading rates decreased substantially (baseline 98.4±14.2 N/s to 12-week 71.3±12.1 N/s; 27.5% reduction; p<0.001; d=1.89). Tibialis posterior peak activation timing shifted earlier in stance phase, with mean absolute amplitude increasing 31.2% during loading response (p<0.001). Soleus activation amplitude increased 24.8% with enhanced eccentric control during early stance (p<0.001). Electromyographic analysis revealed improved tibialis posterior-soleus coactivation pattern efficiency, with cross-correlation coefficient improving from 0.52±0.12 baseline to 0.78±0.09 at 12 weeks (p<0.001), indicating enhanced synergistic control. Three-dimensional kinematic analysis demonstrated reduced ankle supination velocity during loading response (baseline 52.3±9.1°/s to 12-week 34.2±7.8°/s; p<0.001), reduced knee flexion asymmetry (baseline 8.6±3.2° to 12-week 3.1±2.4°; p<0.001), and improved hip extension at terminal swing (baseline 18.4±5.2° to 12-week 26.1±4.8°; p<0.001). Finite element modeling demonstrated 34.7% reduction in peak medial tibial von Mises stress and 29.3% reduction in compressive strain in the injury-vulnerable distal tibial region. Biomechanical adaptations demonstrated substantial persistence at 6-month follow-up assessment (92.1% of peak tibial acceleration reduction maintained; 87.4% of loading rate reduction sustained), with adaptation degradation correlating significantly with post-intervention exercise adherence (r=0.71; p<0.001). Conclusion: Combined gait retraining and neuromuscular strengthening produces integrated biomechanical adaptations substantially reducing tibial loading stresses through synchronized muscle activation patterns, normalized kinematics, and optimized joint reaction forces. Mechanistic understanding reveals that intervention efficacy derives from coordinated modifications across multiple biomechanical domains rather than isolated single-parameter improvements. Sustained biomechanical adaptations at 6-month follow-up indicate durable neuromotor learning and tissue remodeling, with maintenance contingent upon continued physical activity. Findings provide mechanistic validation for integrating gait retraining with neuromuscular training and underscore the translational importance of comprehensive biomechanical assessment in MTSS rehabilitation research.
Selva et al. (Mon,) studied this question.