Neuromuscular adaptations to eccentric strength training in children and adolescents with cerebral palsy

To determine the neuromuscular outcomes of an eccentric strength-training programme for children and adolescents with cerebral palsy (CP).

In this randomised, parallel-group trial with waiting control, 14 participants with CP (six males, eight females; mean age 11y, SD 2y range 9-15y), diagnosed with upper-limb spasticity were compared with 14 age- and sex-matched typically developing participants. Participants with CP completed a 6-week progressive resistance-strengthening programme, performing eccentric lengthening contractions of their upper limb three times a week. Data from dynamometer and surface electromyography (EMG) assessments included peak torque normalised to body mass (T/Bm), work normalised to body mass (W/Bm), angle at peak torque, curve width, and EMG activation.

After training, children with CP had improved eccentric T/Bm (p=0.009) and W/Bm (p=0.009) to a level similar to that of the typically developing children. No change in angle of peak torque occurred, although curve width increased both concentrically (p=0.018) and eccentrically (p=0.015). EMG activity was elevated before training in children with CP but decreased with training to levels similar to those of the typically developing children.

With eccentric strength training, children with CP increased torque throughout range of motion. Results suggest that eccentric exercises may decrease co-contraction, improving net torque development. Eccentric actions may be important in the maintenance of the torque-angle relationship. These results have significant implications for the prescription of strength-training programmes for people with CP.