Trajectories of cardiorespiratory fitness in children with and without developmental coordination disorder: a longitudinal analysis.

OBJECTIVE: To compare the longitudinal trajectories of cardiorespiratory fitness (CRF) in children with probable developmental coordination disorder (DCD) with those of typically developing children. SETTING: School-based study, conducted in a large region of Ontario, Canada. 75 out of a possible 92 schools (83%) consented to participate. PARTICIPANTS: A cohort of children, enrolled in grade 4 (mean 9 years 11 months; SD 0.05) at baseline (n=2278) were followed twice-yearly over a 2-year period. MEASURES: The short form of the Bruininks-Oseretsky test of motor proficiency was used to identify children with probable DCD and the Leger shuttle run to measure maximal oxygen uptake (VO(2)max). RESULTS: Mixed-effects modelling was used to estimate the change over time in predicted VO(2)max for both children with probable DCD and typically developing children. For all children, VO(2)max declined over time. Children (boys and girls) with probable DCD not only had lower VO(2)max at baseline compared with typically developing children, VO(2)max declined among these children at a much steeper rate. CONCLUSION: Although previous research has found children with DCD to have poor CRF compared with typically developing children, most of this work has relied on cross-sectional designs to examine group differences. The results of this study confirm that differences in CRF between children with and without probable DCD persist over time, highlighting the concern that DCD is a risk factor for poor cardiovascular health in children.