Relationships among Strength, Body Composition, and Measures of Activity in Ambulatory Children with Cerebral Palsy: A Cross-Sectional Study

The objective of this work was to quantitatively describe the relationships among overall lower extremity strength and body composition with measures of activity in ambulatory children with cerebral palsy (CP). The design was a prospective, multicenter cohort, cross-sectional study among seven pediatric orthopedic facilities. The participants included children ages eight to 18 years (n = 392; 249 male, 143 female), GMFCS levels I– III (I = 155; II = 160; III = 77) with diplegia (n = 280, mean age 12.9 ± 2.7 years) and hemiplegia (n = 112, mean age 12.6 ± 2.9 years). Main outcome measures include lower extremity strength, body composition, and activity. Quantitative relationships among variables were reported using Pearson correlation coefficients with p < 0.001. Results show strength had fair to moderate correlations with GMFM-66 and PODCI global function, sports and physical function, and transfer and basic mobility scores for children with diplegia. Children with hemiplegia demonstrated a fair correlation between strength and GMFM-66 score. For children with diplegia and hemiplegia, BMI was not correlated with measures of function or activity. Body fat percentage demonstrated a fair correlation with PODCI global function scores for children with hemiplegia. Body composition measures had a fair correlation to overall strength for both those with hemiplegia and diplegia. Stronger relationships among measures were observed in higher functioning children. It is concluded that a positive relationship exists between lower extremity strength and measures of activity in ambulatory children with CP. There are multiple factors influencing activity in children with CP, and strength and body composition should not be ignored.