Catch! Movement kinematics of two-handed catching in boys with Developmental Coordination Disorder Sathiskumar Niana Sekaran a , Siobha ´n L. Reid a , Aaron W. Chin b , Silman Ndiaye a , Melissa K. Licari a, * a School of Sport Science, Exercise and Health, The University of Western Australia, Perth, WA, Australia b Vicon Motion Systems, Oxford Metrics Group, Oxford, United Kingdom 1. Introduction Catching is a skill vital for participation in a variety of sports. It requires a precise spatial and temporally coordinated action adjusting to the direction, speed, weight and size of the incoming ball [1,2]. Due to the complex nature of this skill, it comes as no surprise that it is a skill poorly executed by children with Developmental Coordination Disorder (DCD), a disorder charac- terised by the inability to perform movement skills at an age appropriate level [3]. Unfortunately the condition is poorly under- stood, despite the frequent occurrence in the childhood population (6%) [3], in particular the factors contributing to poor skill execution. Previous research examining the catching performance of children with DCD has demonstrated that it is less advanced, with children presenting with immature patterns of coordination [4]. The majority of studies have been qualitative in nature [4–8], with children with DCD found to have difficulty predicting ball flight, controlling posture, and organising and initiating segments [6,7,9], resulting in reduced catching success. Research has evaluated movement based errors seen in hand, arm, trunk and foot positioning during the catch. While these observational studies have provided valuable insight into common errors made, discrete movement errors are likely to be missed. Therefore, there is an opportunity for further research to address these limitations using more sophisticated measurement techniques. To date, limited studies have examined catching performance in DCD using three-dimensional movement analysis [10–14]. Those that have, suggest that children with DCD rigidly fixate and couple their upper limbs [10,13], exhibit errors during the transport and grasp phases [12], and display less adaptable movement strategies [14]. While these studies have provided greater insight into the catching deficiencies of this population, they are not without design limitations, including: (i) investigating broad age ranges of children, (ii) selection of children who fall into the ‘at risk’ category of this disorder (between 5 and 15th percentile), and (iii) using less sophisticated 3D motion analysis systems and techniques. The latter (iii) is of particular concern, with studies employing three camera configurations, sampling at a frequency of 50 Hz, and using eight or less reflective markers placed at joint centres to determine upper limb kinematics primarily in the sagittal plane. Placement of markers over joints can result in excessive skin movement artefact and misidentification of anatomical landmarks resulting in significant errors in the calculation of joint kinematics [15,16]. Based on these limitations, further research is needed to accurately quantify catching in this population using a clearly defined sample and more stringent and robust analysis techniques. This study aimed to analyse initiation and sequencing of upper limb segments, as well as the degree of symmetry between the Gait & Posture 36 (2012) 27–32 ARTICLE INFO Article history: Received 18 April 2011 Received in revised form 2 November 2011 Accepted 8 December 2011 Keywords: Developmental Coordination Disorder Catching Kinematics 3D motion analysis ABSTRACT Purpose: To quantify two-handed catching in boys with Developmental Coordination Disorder (DCD) by examining sequencing of the upper limb and trunk segments, and degree of symmetry. Method: Thirteen boys with DCD ( ¯ x ¼ 9:36 years  0.68) and 13 Controls ( ¯ x ¼ 9:16 years  0.68) participated. Children performed 10 two-handed central catching trials, with the best five trials selected for analysis. Results: The DCD group displayed greater variability in range of motion across all joint rotations in the catch phase. Specifically, increased shoulder flexion, thorax extension and elbow extension. Although the initiation of segmental movement occurred in the same order for the two groups, the DCD group initiated wrist extension considerably earlier. The DCD group also exhibited significant asymmetry in elbow flexion–extension. Conclusion: Despite success in performing this simple catching task (88% successful), the DCD group displayed an inefficient, variable and less symmetrical catching technique. ß 2011 Elsevier B.V. All rights reserved. * Corresponding author at: School of Sport Science, Exercise and Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia. Tel.: +61 8 6488 2361; fax: +61 8 6488 1039. E-mail address: melissa.licari@uwa.edu.au (M.K. Licari). Contents lists available at SciVerse ScienceDirect Gait & Posture journal homepage: www.elsevier.com/locate/gaitpost 0966-6362/$ – see front matter ß 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.gaitpost.2011.12.010