Comparison of Single and Double Inverted Pendulum Models in Determining Cerebral Palsy Trunk Muscles in Sitting Position: A Subject Specific Approach

Most of CP patients, especially those with severe CP, spend much of their time sitting to perform vital tasks of daily life. In this single subject specific study, the objective is to identify cerebral palsy trunk muscles activity in sitting position. Three dimensional single and double inverted pendulum models are used to study upper body movements. A quadriplegia spastic cerebral palsy and a normal control subject participated in the experiment. Three markers were placed on the bony landmarks of S1, T10, and C7. Data representing the electromyographic activity of the muscles along with the kinematic results of motion analysis were recorded simultaneously. Static optimization approach is used to solve the problem. Muscle force patterns and moments of muscles are obtained using two biomechanical models. In controlling trunk posture, CP subject moves the upper body like a single inverted pendulum.