The relationship between joint mobility and motor performance in children with and without the diagnosis of developmental coordination disorder

Background: The purpose of this study was to determine whether joint mobility is associated with motor performance in children referred for Developmental Coordination Disorder (DCD-group) in contrast to a randomly selected group of children between 3-16 years of age (Random-Group). Methods: 36 children with DCD and 352 typically developing children (Random-Group) participated. Hypermobility was classified based on the Beighton score (cut-off >= 5 for 3-9 years and >= 4 for 10-16 years) using goniometry. Motor performance was assessed with the Movement Assessment Battery for Children (MABC). Results: The mean Beighton score in the DCD-group was 5.0 versus 2.6 in the Random group. Prevalence of hypermobility was higher in the DCD-group than in the Random Group (64% and 33% respectively; X-2 = 16.09, p <.001). There was a significant [negative] correlation (r(p) = -.38, p = .02) between Beighton score and total MABC scores within the DCD group, but not in the Random Group (r(p) = -0.07, p = .20). More specifically, in the DCD group we found a significant negative correlation between the MABC total score and the degree of hyperextension of the knees. Conclusion: The extremely high prevalence of hypermobility when applying the recommended cut-off scores stresses the need for an international agreement on firm cut-off points and the use of standardized measurement of Beighton mobility manoeuvres. The results of this study show that a cut-off of 7 is more appropriate, resulting in a prevalence of 6% in children aged 3-16 years. Although in the general population motor performance and joint mobility are not related, this is the case in children referred for DCD. We argue that more mobility of the joints may be a disadvantage when motor coordination is poorly developed