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A comparison of leg stiffness in running between typically developing children and children with cerebral palsy
A Chappell1, G T Allison1, N Gibson2
1School of Physiotherapy and Exercise Sciences, Curtin University, Kent St., Bentley, WA 6102, Australia.
Insights
Children with cerebral palsy exhibit altered leg stiffness during running, impacting their efficiency and speed. This difference varies based on the severity of their condition, as classified by the Gross Motor Function Classification Scale.
Area of Science:
- Biomechanics
- Pediatric Neurology
- Movement Science
Background:
- Leg stiffness is crucial for efficient running by utilizing the stretch-shortening cycle.
- Neuromuscular impairments in children with cerebral palsy (CP) can lead to altered leg stiffness.
- Understanding these alterations is key to improving mobility and performance in children with CP.
Purpose of the Study:
- To quantify and compare leg stiffness during running in typically developing children and those with CP (GMFCS levels I and II).
- To investigate how leg stiffness varies across different speeds (jogging, running, sprinting) in these groups.
- To identify potential differences in leg stiffness between affected and non-affected limbs in children with CP.
Main Methods:
- A cross-sectional study involving kinematic data collection from typically developing children and children with CP (GMFCS I and II).
- Analysis of ground reaction forces, leg length changes, and 3D leg stiffness during various running speeds.
- Statistical analysis using linear mixed models to compare leg stiffness between groups.
Main Results:
- Children with CP demonstrated reduced leg stiffness during jogging and running compared to typically developing peers.
- Affected legs in children with CP (GMFCS I) showed significantly less stiffness than non-affected legs during running and sprinting.
- Leg stiffness differences were observed to be dependent on the functional classification (GMFCS level) of the children with CP.
Conclusions:
- Children with cerebral palsy exhibit distinct leg stiffness patterns during running.
- These atypical leg stiffness profiles are influenced by the child's functional classification (GMFCS level).
- Findings highlight the need for tailored interventions to address altered biomechanics in children with CP.
Background:
Leg stiffness is important during running to increase velocity and maximise efficiency by facilitating use of the stretch-shortening cycle. Children with cerebral palsy who have neuromuscular impairments may have altered leg stiffness. The aim of this study was to describe leg stiffness during running in typically developing children and those with cerebral palsy in Gross Motor Function Classification Scale levels I and II at a range of speeds.
Methods:
This cross-sectional study examined kinematic data collected from typically developing children (n = 21) and children with cerebral palsy (Gross Motor Function Classification Scale level I n = 25, Gross Motor Function Classification Scale level II n = 13) during jogging, running and sprinting. Derived variables were resultant ground reaction force, change in leg length and three-dimensional leg stiffness. Linear mixed models were developed for statistical analysis.
Findings:
Children with cerebral palsy had reduced stiffness when jogging (Gross Motor Function Classification Scale level I affected t = 3.81 p < 0.01; non-affected t = 2.19 p = 0.03; Gross Motor Function Classification Scale level II affected t = 2.04 p = 0.04) and running (Gross Motor Function Classification Scale level I affected t = 3.23 p < 0.01) compared to typically developing children. Affected legs were less stiff than non-affected legs only in Gross Motor Function Classification Scale level I during running (t = 2.26 p = 0.03) and sprinting (t = 2.95 p < 0.01).
Interpretation:
Children with cerebral palsy have atypical leg stiffness profiles which differ according to functional classification.
