Physical fitness in children with Developmental Coordination Disorder: Measurement matters Gillian D. Ferguson a,b, *, Wendy F.M. Aertssen c , Eugene A.A. Rameckers c,d , Jennifer Jelsma a , Bouwien C.M. Smits-Engelsman b a 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 b 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 c Avans + University of Professionals, Department of Physiotherapy, Heerbaan 14-40, Postbox 2087, 4800 CB Breda, The Netherlands d Maastricht University Medical Centre, Department of Rehabilitation Medicine & Adelante Center of Expertise in Rehabilitation & Audiology, P.O. Box 616, 6200 MD Maastricht, The Netherlands 1. Introduction The American College of Sports Medicine (ACSM) defines physical fitness as a set of measurable health and skill-related attributes that include body composition, cardiorespiratory fitness (CRF), muscular fitness, flexibility, and neuromotor Research in Developmental Disabilities xxx (2014) xxx–xxx ARTICLE INFO Article history: Received 13 December 2013 Received in revised form 29 January 2014 Accepted 29 January 2014 Available online xxx Keywords: Physical fitness Strength Anaerobic muscle capacity Muscle power Aerobic capacity Developmental Coordination Disorder South Africa 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 = 8y 1mo) and Typically Developing (TD) children (n = 70, 35 boys, mean age = 7y 9mo) 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 30 s) 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. ß 2014 Elsevier Ltd. All rights reserved. * Corresponding author at: University of Cape Town, Department of Health and Rehabilitation Sciences, Suite F45: Old Main Building, Groote Schuur Hospital, Main Road, Observatory 7925, Cape Town 8000, South Africa. Tel.: +27 21 406 6045; mobile: +27 82 9743924. E-mail addresses: gillian.ferguson@uct.ac.za (G.D. Ferguson), wendyverhoef@live.nl (Wendy F.M. Aertssen), eaa.rameckers@hetnet.nl (Eugene A.A. Rameckers), jennifer.jelsma@uct.ac.za (J. Jelsma), bouwiensmits@hotmail.com (Bouwien C.M. Smits-Engelsman). G Model RIDD-2199; No. of Pages 11 Please cite this article in press as: Ferguson, G. D., et al. Physical fitness in children with Developmental Coordination Disorder: Measurement matters. Research in Developmental Disabilities (2014), http://dx.doi.org/10.1016/ j.ridd.2014.01.031 Contents lists available at ScienceDirect Research in Developmental Disabilities http://dx.doi.org/10.1016/j.ridd.2014.01.031 0891-4222/ß 2014 Elsevier Ltd. All rights reserved.