Growth and muscle strength development in children with developmental coordination disorder

Abstract

Aim: To assess effects of growth on lower limb maximal isometric muscle strength (MIMS) development in children with developmental coordination disorder (DCD). Method: This observational study used hand-held dynamometry to evaluate MIMS (hip abductors, flexors, extensors; knee flexors and extensors; ankle dorsiflexors) in children with DCD (n=33, 12 females, 21 males, 6–12y, mean [SD] age 9y [2y]). Regression analysis compared changes in MIMS for similar changes in growth (height or body mass) for children with DCD and typically developing children (pre-existing database, n=183), controlling for age and sex. Results: For the same height gain, the gain in muscle strength was 37.3% to 69.2% less in children with DCD compared with typically developing children, with significantly lower slopes (p-value between <0.001–0.042) in all muscle groups tested except knee extensors and ankle dorsiflexors in females. Strength gains related to body mass gains were not different for children with DCD compared to typically developing children. Interpretation: Even when growing at a similar rate, children with DCD do not develop muscle strength gains at the same rate as their typically developing peers. What this paper adds: Strength gains with growth (height) may be reduced in children with developmental coordination disorder.