Related Experiment Video
Updated: Jun 25, 2026
Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI
Published on: April 18, 2011
Temporal characteristics of lower extremity moment generation in children with cerebral palsy
Andrea L Downing1, Kathleen J Ganley, Deanne R Fay
1Center for Adaptive Neural Systems, PO Box 874404, Arizona State University, Tempe, Arizona 85287-4404, USA. andrea.downing@asu.edu
Insights
Children with cerebral palsy (CP) exhibit impaired lower extremity strength and slower muscle activation and relaxation times. Therapeutic interventions should address both strength and timing for improved motor function in CP.
Area of Science:
- Biomedical Engineering
- Pediatric Physical Therapy
- Neurology
Background:
- Lower extremity weakness is a known issue in children with cerebral palsy (CP).
- The temporal aspects of muscle force generation in CP are not well understood but may impact function.
Purpose of the Study:
- To characterize the temporal properties of ankle, knee, and hip flexion/extension moment generation in children with CP.
- To compare these temporal characteristics with those of able-bodied children.
- To explore correlations between temporal measures, maximal voluntary isometric contractions (MVICs), and the Gross Motor Function Measure-66 (GMFM-66).
Main Methods:
- Quantified MVICs, maximum rates of moment development and relaxation, and time to produce/reduce moments.
- Compared these measures between children with CP and a control group of able-bodied children.
- Analyzed relationships between temporal measures, MVICs, and GMFM-66 scores.
Main Results:
- Children with CP demonstrated significantly lower MVICs, reduced maximum rates of moment development and relaxation, and prolonged times to produce and reduce moments compared to controls.
- Correlations were found between joint-specific maximum rates of moment development/relaxation and both GMFM-66 scores and MVICs in children with CP.
Conclusions:
- Children with CP exhibit deficits not only in the magnitude of lower extremity muscle strength but also in the timing of force generation and relaxation.
- Both strength and temporal control of muscle moments are critical targets for effective physical therapy interventions in pediatric cerebral palsy.
Abstract:
Lower extremity weakness has been documented in children with cerebral palsy (CP). However, the temporal characteristics of moment generation have not been characterized, and they may be important to function. This study tested ankle, knee, and hip flexion and extension moment generation capabilities in children with CP and in able-bodied children. Maximum voluntary isometric contractions (MVIC), the maximum rates of moment development and relaxation, and the time to produce and reduce the moments were quantified. Relationships between the temporal measures, Gross Motor Function Measure-66 (GMFM-66), and MVICs were also examined. Children with CP had significantly reduced MVICs, maximum development, and relaxation rates, and increased times to produce and reduce moments. The maximum rates of moment development and relaxation at some joints were correlated with the GMFM-66 and MVICs. These results suggest that both the magnitude and temporal characteristics of moment generation need to be targeted during therapeutic interventions for children with CP.
