Symptom-Region-Associated Neuromechanical Compensation During Running: Integrated 3D Kinematic, Kinetic and Electromyographic Profiling of Running-Related Injuries

Background and Objectives: Running-related injuries (RRIs) are common musculoskeletal conditions associated with repetitive loading and heterogeneous biomechanical adaptations. This study evaluated the clinical utility of integrated three-dimensional (3D) biomechanical assessment for identifying interlimb asymmetries and symptom-region-specific compensatory strategies in runners with RRIs. Methods: One hundred twenty-two adolescent and adult runners referred from a Sports Medicine Physical Therapy clinic for a running-related musculoskeletal complaint were classified by primary symptomatic region (spine, n = 10; hip, n = 38; knee, n = 48; foot/ankle, n = 26); 27 asymptomatic runners served as controls. Participants completed standardized treadmill running while bilateral markerless 3D kinematics, instrumented treadmill kinetics, and surface electromyography (sEMG) were synchronously recorded. Log-transformed asymmetry indices and neuromechanical outcomes were evaluated using mixed-effects models with false discovery rate correction. Results: Distinct symptom-region-associated patterns of mechanical and neuromuscular compensation were identified. Hip-region RRIs demonstrated greater contralateral propulsive impulse (diff = 0.07; p = 0.029), whereas knee-region RRIs demonstrated greater contralateral hip extension moment (diff = 0.14; p = 0.013). Foot/ankle-region RRIs demonstrated greater contralateral knee extension moment (diff = 0.18; p = 0.017) and greater symptomatic-limb tibialis anterior activation (peak RMS: diff = 0.52; p = 0.032). The spine-region cohort demonstrated greater dominant-limb medial gastrocnemius activation (peak RMS: diff = 0.35; p = 0.037). Conclusions: Integrated 3D kinematic, kinetic, and neuromuscular profiling identified distinct regional patterns of load redistribution across the kinetic chain in runners with RRIs. This multimodal framework may complement clinical examination by identifying individualized biomechanical targets for rehabilitation and enabling longitudinal assessment of load-sharing recovery.