The effects of electromyography-assisted modelling in estimating musculotendon forces during gait in children with cerebral palsy

This study evaluated four different forms of neuro-musculoskeletal modelling estimating musculotendon forces during gait in children with cerebral palsy and typically developing (TD) children. A scaled-generic musculoskeletal model for each child was used, estimating musculotendon forces by, i.e. I) static optimization (SO) minimizing summed-excitation squared; II) SO with maximum isometric muscle forces scaled to body mass; III) an EMG-assisted (EA) approach using optimization to minimize summed-excitation squared while reducing tracking errors of experimental EMG-linear envelopes and joint moments; and IV) EA with musculotendon model parameters first personalised by calibration. Models were assessed by comparing their outcomes with measured EMG-linear envelopes and joint moments. Models using SO showed a relatively low model performance. EA approaches performed much better, especially in CP. Therefore, this study highlights the importance of EMG-assisted modelling when estimating musculotendon forces in TD and even more in children with CP.