title: Longitudinal examination of objectively-measured physical activity and sedentary time among children with and without significant movement impairments.
abstract: BACKGROUND
  Children with Developmental Coordination Disorder (DCD) tend to be less active than typically-developing (TD) children. Current evidence, however, is based on cross-sectional and self-reported activity, and little is known about sedentary time among children with significant movement impairments such as DCD. The current study examines the longitudinal patterns of objectively measured physical activity and sedentary time in children with and without possible DCD (pDCD).
  
  
  METHODS
  Data is from a longitudinal nested case-control study, with 103 participants (n=60 males ages=12 and 13 at baseline). Participants averaging ⩽16th percentile on the Movement Assessment Battery for Children were considered having significant movement impairments and pDCD (n=49). All participants wore accelerometers for seven days.
  
  
  RESULTS
  There were significant main effects for time (Estimate=-23.98, p<.01) and gender (Estimate=59.86, p<.05) on total physical activity, and time spent being sedentary (Estimate=15.58, p<.05). Significant main effects for pDCD (Estimate=-5.38, p<.05) and gender (Estimate=26.89, p<.01), and time by gender interaction (Estimate=-7.50, p<.05) were found for moderate-to-vigorous physical activity (MVPA). Sedentary time did not differ between children with and without DCD.
  
  
  CONCLUSIONS
  Results suggest children with pDCD engaged in less MVPA compared to TD children. Consistent patterns of MVPA over time, however, suggest that the divergence in MVPA occurs earlier in childhood. Further longitudinal research following a younger cohort is necessary to identify the specific point that differences in MVPA emerge.
authors.affiliation: Department of Family Medicine, McMaster University, Hamilton, ON, Canada; Michael G. DeGroote School of Medicine, Niagara Regional Campus, McMaster University, St. Catharines, ON, Canada. Electronic address: kwanmy@mcmaster.ca.
authors.forename: Matthew Y W
authors.initials: MYW
authors.lastname: Kwan
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, ON, Canada.
authors.forename: Sara
authors.initials: S
authors.lastname: King-Dowling
authors.affiliation: Department of Health Sciences, Brock University, St. Catharines, ON, Canada.
authors.forename: John A
authors.initials: JA
authors.lastname: Hay
authors.affiliation: Department of Health Sciences, Brock University, St. Catharines, ON, Canada.
authors.forename: Brent E
authors.initials: BE
authors.lastname: Faught
authors.affiliation: Department of Family Medicine, McMaster University, Hamilton, ON, Canada; Department of Kinesiology, McMaster University, Hamilton, ON, Canada; Department of Psychiatry and Behavioural Neurosciences and Clinical Epidemiology and Biostatistics, CanChild Centre for Childhood Disability Research, and Offord Centre for Child Studies, McMaster University, Hamilton, ON, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Cairney
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015233:Models, Statistical; D019957:Motor Skills Disorders / Q000503:physiopathology*; D057185:Sedentary Behavior; D013997:Time Factors
keywords: Accelerometry; DCD; MVPA; Movement impairments; Physical activity; Sedentary