Analysis of the relationships that body composition and muscular strength have with oxygen cost of walking in children with cerebral palsy

- We examine relationships of strength, BMI and body fat to oxygen cost of walking.
- Being stronger may be related to efficient ambulation.
- Higher BMI or percent body fat is not related to oxygen cost of walking.
- Higher BMI may be related to a slower preferred walking speed.

ObjectiveTo investigate whether body composition and lower extremity strength relate to oxygen cost of walking in children with cerebral palsy (CP), and to evaluate the relative contributions of these measures to explain variation in oxygen cost seen in this population.MethodsA total of 116 children with spastic diplegic CP, Gross Motor Function Classification System levels I-III, aged 8-18 participated. Strength, body composition (body mass index (BMI) and percent body fat) and oxygen cost were recorded. Pearson correlations assessed relationships between variables of body composition and strength to oxygen cost. Forward stepwise linear regression analyzed variance explained by strength and body composition measures. Oxygen data were analyzed by weight status classifications using one-way analysis of variance with significance set at p < 0.05.ResultsTotal strength (r = −0.27) and total extensor strength (r = −0.27) had fair inverse relationships with oxygen cost. Total extensor strength explained 7.5% (r2 = 0.075, beta = −0.274, p < 0.01) of the variance in oxygen cost. Body composition did not explain significant variance in oxygen cost, however significant differences were found in oxygen consumption (p = 0.003) and walking velocity (p = 0.042) based on BMI weight classifications.ConclusionsFor ambulatory children with CP, oxygen cost during walking can be partially explained by total extensor strength and not body composition. However, those categorized as obese may adjust to a slower walking speed to keep their oxygen cost sustainable, which may further affect their ability to keep up with typically developing peers and possibly lead to greater fatigue.