Lower limb muscle strength in children with developmental coordination disorder: a pilot study

Purpose: This study aimed to compare the maximal isometric muscle strength of the major lower limb muscles between children with DCD and those with typical development. Methods: Eighty-six children with DCD (65 boys and 21 girls; mean age ± standard deviation = 7.8 ± 1.5 years) and 99 typically-developing children (56 boys and 43 girls; mean age ± standard deviation = 7.4 ± 1.4 years) participated in this study voluntarily. Isometric peak forces of the hip flexors, hip extensors, hip abductors, knee flexors, knee extensors, ankle dorsiflexors and ankle plantar flexors of the non-dominant lower extremity were quantified by a hand-held dynamometer. Body weight and height were also measured using a medical weight scale. Results: Multivariate analysis of covariance (covariates = body mass index and sex) results revealed that children with DCD s lower limb muscle peak forces were 5.9-29.7% lower when compared to typically-developing children. Specifically, children with DCD had lower hip flexor (p < 0.001), hip extensor (p = 0.016), knee flexor (p = 0.033), knee extensor (p = 0.010), ankle dorsiflexor (p < 0.001) and ankle plantar flexor (p 0.05). Conclusion(s): Children with DCD had lower isometric peak forces in their lower limb muscles than typically-developing children. Implications: Further study should examine the impact of this muscular deficit on motor performance in children with DCD. Our results also hint that lower limb muscle strengthening exercise should be incorporated into the rehabilitation program for children with DCD. Key-Words: 1. Clumsy children 2. muscular performance 3. rehabilitation Funding Acknowledgements: This study was partially supported by an ECS grant (27100614) from the Research Grants Council of Hong Kong. Ethics Approval: Human Research Ethics Committee, the University of Hong Kon