Purpose: The study was designed to determine whether relationships exist among knee muscle spasticity, isometric knee muscle strength, knee muscle balance, gross motor function, and walking efficiency in children with spastic cerebral palsy and to evaluate the relative contributions of impairment measures to functional outcome measures.
Methods: Twenty-seven children with spastic diplegic cerebral palsy participated. Knee muscle strength and spasticity were measured by a hand-held dynamometer and the Ashworth Scale, respectively. Functional abilities were assessed by the Gross Motor Function Measure and by calculating the energy expenditure index from data collected during two three-minute walk tests (comfortable and fast speeds).
Results: Significant relationships were found between impairments and functional abilities (r = 0.42-0.85, p < 0.05). Isometric hamstring strength and quadriceps spasticity explained 81.5% of total Gross Motor Function Measure score variance. Quadriceps spasticity explained 56.7% of energy expenditure index variance during comfortable walking.
Conclusion: Hamstring strength and quadriceps spasticity explain much of the variance in gross motor function and comfortable walking efficiency.