Sarshari, EhsanMancuso, MatteoTerrier, AlexandreFarron, AlainMullhaupt, PhilippePioletti, Dominique2020-10-252020-10-252020-10-25202110.1080/10255842.2020.1814755https://infoscience.epfl.ch/handle/20.500.14299/172746WOS:000577409400001Estimation of muscle forces in over-actuated musculoskeletal models involves optimal distributions of net joint moments among muscles by a standard load-sharing scheme (SLS). Given that co-contractions of antagonistic muscles are counterproductive in the net joints moments, SLS might underestimate the co-contractions. Muscle co-contractions play crucial roles in stability of the glenohumeral (GH) joint. The aim of this study was to improve estimations of muscle co-contractions by incorporating electromyography (EMG) data into an upper limb musculoskeletal model. To this end, the model SLS was modified to develop an EMG-assisted load-sharing scheme (EALS). EMG of fifteen muscles were measured during arm flexion and abduction on a healthy subject and fed into the model. EALS was compared to SLS in terms of muscle forces, GH joint reaction force, and a stability ratio defined to quantify the GH joint stability. The results confirmed that EALS estimated higher muscle co-contractions compared to the SLS (e.g., above 50 N higher forces for both triceps long and biceps long during arm flexion).Computer Science, Interdisciplinary ApplicationsEngineering, BiomedicalComputer ScienceEngineeringmuscle over-actuationsinverse dynamicsmuscle force estimationsantagonistic muscle co-contractionshill-type modelsforce predictionshoulderoptimizationjointcriteriontext::journal::journal article::research article