Biomechanical Effects of Lower-Limb Asymmetry During Running: An OpenSim Computational Study

Symmetry and asymmetry significantly influence running biomechanics, performance, and injury risk. Given the practical, ethical, and methodological constraints inherent in human-subject studies, computational modeling emerges as a valuable alternative for exploring biomechanical asymmetries in detail. This study systematically evaluated the biomechanical effects of lower limb asymmetry during running using computational musculoskeletal modeling in OpenSim. By simulating controlled asymmetries in limb strength, stride length, and ground reaction forces (±5% and ±10%), we quantified alterations in joint moments, ground reaction forces (GRF), and muscular activation patterns. Results demonstrated significant biomechanical deviations under asymmetric conditions, with vertical GRF decreasing by up to 15% on the weaker limb and increasing by up to 13% on the stronger limb. Peak knee joint moments increased by up to 20% on the stronger limb under pronounced asymmetry. Muscular activation of key lower limb muscles, such as the gastrocnemius and quadriceps, increased substantially (up to 25%) to compensate for mechanical imbalance. These findings clearly illustrate the detrimental impact of asymmetrical loading, emphasizing the increased injury risks associated with limb asymmetry. Computational modeling proved to be a robust, ethical, and economically viable approach, offering practical insights that can directly inform targeted training and injury-prevention interventions.