title: Physical fitness in children with developmental coordination disorder: measurement matters.
abstract: Children with Developmental Coordination Disorder (DCD) experience considerable difficulties coordinating and controlling their body movements during functional motor tasks. Thus, it is not surprising that children with DCD do not perform well on tests of physical fitness. The aim of this study was to determine whether deficits in motor coordination influence the ability of children with DCD to perform adequately on physical fitness tests. A case-control study design was used to compare the performance of children with DCD (n=70, 36 boys, mean age=8 y 1 mo) and Typically Developing (TD) children (n=70, 35 boys, mean age=7 y 9 mo) on measures of isometric strength (hand-held dynamometry), functional strength, i.e. explosive power and muscular endurance (Functional Strength Measurement), aerobic capacity (20 m Shuttle Run Test) and anaerobic muscle capacity, i.e. muscle power (Muscle Power Sprint Test). Results show that children with DCD were able to generate similar isometric forces compared to TD children in isometric break tests, but were significantly weaker in three-point grip strength. Performance on functional strength items requiring more isolated explosive movement of the upper extremities, showed no significant difference between groups while items requiring muscle endurance (repetitions in 30s) and items requiring whole body explosive movement were all significantly different. Aerobic capacity was lower for children with DCD whereas anaerobic performance during the sprint test was not. Our findings suggest that poor physical fitness performance in children with DCD may be partly due to poor timing and coordination of repetitive movements.
authors.affiliation: University of Cape Town, Faculty of Health Sciences, Department of Health and Rehabilitation Sciences, Suite F45: Old Main Building, Groote Schuur Hospital, Main Road, Observatory 7925, Cape Town 8000, South Africa; Katholieke Universiteit Leuven, Faculty of Kinesiology and Rehabilitation Sciences, Department of Kinesiology, Movement Control and Neuroplasticity Research Group, Tervuursevest 101, Postbox 1501, B-3001 Heverlee, Belgium. Electronic address: gillian.ferguson@uct.ac.za.
authors.forename: Gillian D
authors.initials: GD
authors.lastname: Ferguson
authors.affiliation: Avans + University of Professionals, Department of Physiotherapy, Heerbaan 14-40, Postbox 2087, 4800 CB Breda, The Netherlands. Electronic address: wendyverhoef@live.nl.
authors.forename: Wendy F M
authors.initials: WF
authors.lastname: Aertssen
authors.affiliation: Avans + University of Professionals, Department of Physiotherapy, Heerbaan 14-40, Postbox 2087, 4800 CB Breda, The Netherlands; Maastricht University Medical Centre, Department of Rehabilitation Medicine & Adelante Center of Expertise in Rehabilitation & Audiology, P.O. Box 616, 6200 MD Maastricht, The Netherlands. Electronic address: eaa.rameckers@hetnet.nl.
authors.forename: Eugene A A
authors.initials: EA
authors.lastname: Rameckers
authors.affiliation: University of Cape Town, Faculty of Health Sciences, Department of Health and Rehabilitation Sciences, Suite F45: Old Main Building, Groote Schuur Hospital, Main Road, Observatory 7925, Cape Town 8000, South Africa. Electronic address: jennifer.jelsma@uct.ac.za.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Jelsma
authors.affiliation: Katholieke Universiteit Leuven, Faculty of Kinesiology and Rehabilitation Sciences, Department of Kinesiology, Movement Control and Neuroplasticity Research Group, Tervuursevest 101, Postbox 1501, B-3001 Heverlee, Belgium. Electronic address: bouwiensmits@hotmail.com.
authors.forename: Bouwien C M
authors.initials: BC
authors.lastname: Smits-Engelsman
mesh_terms: D016022:Case-Control Studies; D002648:Child; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D019957:Motor Skills Disorders / Q000503:physiopathology*; D010809:Physical Fitness / Q000502:physiology*; D012420:Running / Q000502:physiology*
keywords: Aerobic capacity; Anaerobic muscle capacity; Developmental Coordination Disorder; Muscle power; Physical fitness; South Africa; Strength