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Mechanical work performed by the legs of children with spastic diplegic cerebral palsy
Max J Kurz1, Wayne A Stuberg, Stacey L DeJong
1Munroe-Meyer Institute for Genetics and Rehabilitation, Physical Therapy Department, University of Nebraska Medical Center, Omaha, Nebraska, USA. mkurz@unmc.edu
Insights
Children with spastic diplegic cerebral palsy exhibit altered leg mechanics, performing work differently on their center of mass during walking. This impacts their ability to lift and redirect their center of mass, potentially increasing walking energy costs.
Area of Science:
- Biomechanics
- Pediatrics
- Neurology
Background:
- Cerebral palsy (CP) often affects motor control, impacting gait.
- Understanding the biomechanical work performed by legs in children with CP is crucial for gait analysis.
Purpose of the Study:
- To evaluate the mechanical work performed by the legs on the center of mass (CoM) in children with spastic diplegic cerebral palsy compared to healthy children.
Main Methods:
- Collected ground reaction forces from four force platforms during walking.
- Calculated mechanical work performed by lead and trail legs on the CoM.
- Compared work parameters between 10 children with CP and 10 healthy controls.
Main Results:
- Children with CP performed significantly more negative work with the lead leg during double support.
- Children with CP performed significantly less positive work with the trail leg during double support.
- Children with CP performed significantly more positive work on the CoM during single support.
Conclusions:
- Children with spastic diplegic cerebral palsy demonstrate impaired ability to perform mechanical work for CoM elevation and redirection.
- Altered leg work in CP may contribute to the observed higher metabolic cost of walking.
Abstract:
The purpose of this investigation was to evaluate the work performed on the center of mass by the legs of children with cerebral palsy. 10 children that were diagnosed as having cerebral palsy with spastic diplegia (Age=9.1+/-2 years), and 10 healthy children with no walking disabilities participated (Age=9.4+/-2 years). We collected individual leg ground reaction forces from four force platforms, and calculated the mechanical work performed on the center of mass by the lead and trail legs. The normalized walking speeds were not significantly (p=0.33) different between the children with cerebral palsy (0.26+/-0.07) and the controls (0.28+/-0.06). The children with cerebral palsy performed significantly more negative work by the lead leg during double support (p=0.0004), and significantly less positive work by the trail leg (p<0.00001). During single support, the children with cerebral palsy performed significantly more positive work on the center of mass (p<0.00001). No significant differences were found for the amount of negative work performed by the leg in single support (p=0.84). Children with spastic diplegic cerebral palsy show a diminished ability to appropriately perform mechanical work by the legs to lift and redirect the center of mass. The altered mechanical work performed by the legs on the center of mass may play a role in the higher metabolic cost for walking noted in children with cerebral palsy.
