A spasticity model based on feedback from muscle force explains muscle activity during passive stretches and gait in children with cerebral palsy - Fig 2

Examples of measured muscle activity (EMG) during fast passive stretches of gastrocnemii (left) and hamstrings (right). Typically, each stretch consists of a pre-stretch phase with low muscle activity corresponding to the baseline activation, a stretch phase with increased muscle activity corresponding to the spastic response, and a hold-phase with sustained muscle activity for the hamstrings and low muscle activity for the gastrocnemii.