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Deficits in eccentric versus concentric torque in children with spastic cerebral palsy
D L Damiano1, T L Martellotta, J M Quinlivan
1Department of Orthopaedics, University of Virginia, Charlottesville, USA. dld6830@bjc.org
Medicine and Science in Sports and Exercise
|February 24, 2001
Summary
Children with spastic cerebral palsy (CP) exhibit reduced knee and ankle torque, with greater deficits in concentric than eccentric muscle actions. Spasticity impacts voluntary force production, showing a bias toward eccentric torque and greater concentric torque decline across speeds.
Area of Science:
- Neurology
- Pediatrics
- Biomechanics
Background:
- Cerebral palsy (CP) is a common neurodevelopmental disorder affecting motor function.
- Spasticity, a hallmark of CP, influences muscle properties and voluntary force generation.
- Understanding force production deficits is crucial for targeted rehabilitation in ambulatory children with CP.
Purpose of the Study:
- To assess isokinetic eccentric peak torque abnormalities in ambulatory children with spastic CP at the knee and ankle.
- To investigate the impact of spasticity on voluntary force production in this population.
- To compare eccentric and concentric torque deficits across different muscle groups and speeds.
Main Methods:
- Isokinetic testing of knee and ankle muscles (extensors, flexors, dorsiflexors, plantarflexors) in 24 children with spastic CP and 20 typically developing children.
- Measurement of eccentric peak torque at 30°/s and concentric peak torque at 30°/s, 60°/s, and 120°/s using a Biodex dynamometer.
- Normalization of peak torque values by body weight and calculation of eccentric to concentric (E/C) peak torque ratios.
Main Results:
- Children with spastic CP showed significantly decreased eccentric and concentric peak torques in all tested muscle groups.
- The relative deficit in eccentric torque was smaller than in concentric torque.
- Concentric torque decrements across speeds were more pronounced in children with CP, except for ankle dorsiflexors; E/C ratios were higher for knee muscles.
Conclusions:
- Ambulatory children with spastic CP demonstrate diminished eccentric and concentric peak torques at the knee and ankle.
- Spasticity influences voluntary force production, characterized by a tendency towards greater eccentric torque and a more significant decline in concentric torque across increasing speeds.
- These findings highlight the complex neuromuscular adaptations in spastic CP and inform therapeutic strategies focused on improving force generation capacity.