Muscle capacity to accelerate the body during gait varies with foot position in cerebral palsy

Abstract

BackgroundChildren with cerebral palsy (CP) often have altered gait patterns compared to their typically developing peers. These gait patterns are characterized based on sagittal plane kinematic deviations; however, many children with CP also walk with altered transverse plane kinematics. Research QuestionHow do both altered skeletal alignment and kinematic deviations affect muscles’ capacity to accelerate the body during gait? MethodsA three-dimensional gait analysis was completed for 18 children with spastic CP (12.5 ± 2.9 years; GMFCS level II). Musculoskeletal models were developed for each participant, and tibial torsion, measured during a static standing trial and assessed using motion capture, was incorporated. An induced acceleration analysis was performed to evaluate the capacity of muscles to accelerate the body center of mass throughout stance. Differences between the root-mean-square muscle capacity for children with CP walking with internally rotated, standard, and externally rotated postures were evaluated. ResultsExternally rotated postures resulted in a lower capacity to accelerate the body center of mass compared with internally rotated postures. Both changes in skeletal alignment and kinematics contributed to changes in muscle capacity to accelerate the body. SignificanceAltered transverse plane skeletal alignment and compensatory kinematics should both be considered in surgical treatment of children with CP.