Sarah Astill

Ball catching in children with developmental coordination disorder: control of degrees of freedom

This study investigated two‐handed catching in eight children (four males, four females) aged 7 to 8 years (mean 7y 4mo [SD 3mo]) with developmental coordination disorder (DCD) and their age‐matched controls (AMCs). Kinematic data were collected to examine Bernsteins (1967) notion of freezing and releasing degrees of freedom (DF). Participants were asked to catch a ball 30 times, delivered in three blocks of 10 trials. Video analysis showed that children with DCD caught significantly fewer balls than their AMCs (p≤0.001) counterparts. Kinematic analyses showed that children with DCD exhibited smaller ranges of motion and less variable angular excursions of the elbow joints than their AMCs, and that their elbows are more rigidly coupled (p≤0.001). These data suggest that children with DCD rigidly fix and couple their limbs to reduce the number of DF actively involved in the task.

Movement rehabilitation after spinal cord injuries: Emerging concepts and future directions

Considerable inroads are being made into developing new treatments for spinal cord injury (SCI) which aim to facilitate functional recovery, including locomotion. Research on rehabilitative strategies following SCI using animal models has demonstrated that regaining and maintaining motor function, such as standing or stepping, is governed by principles of skill acquisition. Mechanisms key to learning motor tasks, including retention and transfer of skill, feedback and conditions of practice, all have examples in the SCI animal literature, although the importance of many concepts may often be overlooked. Combinatorial strategies which include physical rehabilitation are beginning to yield promising results. However, the effects of molecular-cellular interventions including chondroitinaseABC, anti-NogoA, foetal stem cell transplantation, etc., are still poorly understood with reference to the changes made to spinal plasticity by training and exercise. Studies that investigate the interplay between rehabilitation and other treatments have had mixed results; it appears likely that precise timings of different interventions will help to maximize recovery of function. Understanding how the time-course of injury and different rehabilitative and treatment modalities might factor into spinal plasticity will be critical in future therapeutic interventions.

Can children with developmental coordination disorder adapt to task constraints when catching two-handed?

Purpose. To compare the nature and extent of inter and intralimb coupling during two-handed catching and the effect of manipulating task constraints in children with Developmental Coordination Disorder (DCD) and their typically developing peers (AMC). Method. Twenty children aged 7 – 10 years, ten with DCD and 10 AMC attempted to catch a ball ten times in condition 1 (C1), ball to the midline; condition 2 (C2), ball to the left shoulder and condition 3 (C3), ball to the right shoulder. Both 3D kinematic data and video data were collected. Results. Children with DCD caught fewer balls than the AMC children, regardless of age or condition (p ≤ 0.001). Children with DCD demonstrated a higher degree of linkage between limbs in C1 and a lower degree of between limb coupling in C2 and C3 when compared to the AMC (p ≤ 0.05). Differences between the AMC7 – 8 and AMC9 – 10 group were found with respect to interlimb coupling. Conclusions. The influence of manipulating task constraints and the individual nature of children with DCD must be considered by those involved in rehabilitation. By doing so, children with DCD may search for appropriate motor solutions to many functional movement tasks required for everyday life.

Developmental sequences of two-handed catching: How do children with and without developmental coordination disorder differ?

The present study examined the movement patterns in children with developmental coordination disorder (DCD) and their age-matched controls (AMC) while catching two-handed. First, a cross-sectional study was conducted to investigate developmental characteristics within the three body component actions (arm, hand, and body) of two-handed catching hypothesized by Haywood and Getchell (). Data analyzed from 36 children (18 DCD, 18 AMC) aged 7–10 years who caught a ball 10 times, two-handed, showed that hypothesized sequences for the arm, hand, and body met the prelongitudinal screening criteria proposed by Roberton (), Langendorfer (), and Roberton, Williams, and Langendorfer (). In light of this, the second part of the study used these sequences to evaluate the movement patterns of 10 children with and 10 without DCD, aged 7–8 years. The data revealed that children with DCD displayed less advanced modal developmental sequence levels than AMC children with respect to the arm and body action components. (p ≤ 0.01) Children with DCD also exhibited less advanced developmental profiles than the AMC children (p ≤ 0.05), the group modal profiles being A2-H2-B2 and A3-H3-B3, respectively. These data also show that each child with DCD exhibited more developmental profiles over the 30 trials than the AMC children (p ≤ 0.01) and that each DCD childs modal developmental profile was unstable (Roberton, ). Thus, over trials children with DCD link together different action patterns of the arm, hand, and body, suggesting that they have not yet developed a stable pattern of coordination to satisfy the task constraints.

Coupling of the Reach and Grasp Phase During Catching in Children With Developmental Coordination Disorder

The authors studied 2-handed catching behavior in 10 children with developmental coordination disorder (DCD), aged 7-10 years old, and their typically developing peers (TDC). Participants performed 15 catches, and the authors examined kinematics of both transport and grasp phases. In terms of the transport phase, movement initiation and movement time was longer and peak deceleration was earlier in children with DCD. In addition, such children initiated the grasp phase earlier, and their maximal grasp aperture was larger. In children with DCD, the time to maximal grasp aperture was more variable, and that aperture was earlier when the authors examined it with respect to the transport phase of the catch. The data suggest that children with DCD may use a decomposition strategy to simplify the movement control of the transport and grasp phases of a catch.

Motor Control, Learning and Development

INTRODUCTION The aim of this book is to provide a resource for undergraduates on sport and exercise science degrees that would also be useful to individuals taking sports coaching courses or training to be physical education teachers or physiotherapists. It is part of the Instant Notes Series and “provides an overview of the key theories, definitions, and measurements of motor control, leading to a discussion on how the human body learns to control movement and the development of motor skills” (back cover). The first author is Director of the Centre for Sport and Exercise Sciences at the University of Leeds, UK and her co-author and former student Sarah Astill is in the School of Health Professions and Rehabilitation Sciences at the University of Southampton, UK.A. What is Motor Control? B. Classification of Skill C. Measurement in Motor Control D. Theories of Control E. Information Processing F. The Central Nervous System (Neurological Issues) G. Sensory Contributions to Control H. Theories of Motor Learning I. Stages of Motor Learning J. Memory K. Implications for Practice L. The Role and Function of Feedback M. Theories of Motor Development N. Development of Fundamental Movement Skills

The influence of perturbing the working surface during reaching and grasping in children with hemiplegic cerebral palsy

Purpose. To examine unimanual and bimanual reaching and grasping in children with hemiplegic cerebral palsy with particular emphasis on the nature and extent of interlimb coupling when the working surface is perturbed. Method. Nine children with hemiplegic cerebral palsy and 7 control children with no movement difficulties took part in the study. Children were asked to pick up a cube unimamually and bimanually when the surface it was placed on was either sloping away from the child (Experiment 1) or towards the child (Experiment 2). Both 3D kinematic data and video data were gathered and qualitative descriptions of video data were made. Results. The working surface did indeed influence the nature and extent of interlimb coupling and this varied from participant to participant. Analysis of the displacement data revealed that during the bimanual condition lower trajectories were produced by both the hemiplegic and non hemiplegic sides, especially in Experiment 2. The control group showed little difference between the unimanual and bimanual condition. Conclusions. Evidence of interlimb coupling is found, these studies support the findings of our previous work that indicates that there are some benefits to performing bimanual movements in children with hemiplegic cerebral palsy.

Multisensory integration in children with Developmental Coordination Disorder

This study examines how multisensory stimuli affect the performance of children with Developmental Coordination Disorder (DCD) on a choice reaction time (CRT) task. Ten children with DCD, identified using the Movement Assessment Battery for Children-2, aged 7-10 years (4F, M=8 y 3 m, SD=17 m) and 10 typically developing peers (TDC) (5F, M=8 y 4 m, SD=17 m) reached to unimodal (auditory (AO), visual (VO)) and bimodal (audiovisual (AV)) stimuli at one of three target locations. A multisensory (AV) stimulus reduced RTs for both groups (p<0.001, η(2)=0.36). While the children with DCD had a longer RT in all conditions, the AV stimulus produced RTs in children with DCD (494 ms) that were equivalent to those produced by the TDC to the VO stimulus (493 ms). Movement Time (DCD=486 ms; TDC=434 ms) and Path Length (DCD=25.6 cm; TDC=24.2 cm) were longer in children with DCD compared to TDC as expected (p<0.05). Only the TDC benefited from the AV information for movement control, as deceleration time of the dominant hand was seen to decrease when moving to an AV stimulus (p<0.05). Overall, data shows children with DCD do benefit from a bimodal stimulus to plan their movement, but do not for movement control. Further research is required to understand if this is a result of impaired multisensory integration.

Bimanual reach to grasp movements after cervical spinal cord injury

Injury to the cervical spinal cord results in bilateral deficits in arm/hand function reducing functional independence and quality of life. To date little research has been undertaken to investigate control strategies of arm/hand movements following cervical spinal cord injury (cSCI). This study aimed to investigate unimanual and bimanual coordination in patients with acute cSCI using 3D kinematic analysis as they performed naturalistic reach to grasp actions with one hand, or with both hands together (symmetrical task), and compare this to the movement patterns of uninjured younger and older adults. Eighteen adults with a cSCI (mean 61.61 years) with lesions at C4-C8, with an American Spinal Injury Association (ASIA) grade B to D and 16 uninjured younger adults (mean 23.68 years) and sixteen uninjured older adults (mean 70.92 years) were recruited. Participants with a cSCI produced reach-to-grasp actions which took longer, were slower, and had longer deceleration phases than uninjured participants. These differences were exacerbated during bimanual reach-to-grasp tasks. Maximal grasp aperture was no different between groups, but reached earlier by people with cSCI. Participants with a cSCI were less synchronous than younger and older adults but all groups used the deceleration phase for error correction to end the movement in a synchronous fashion. Overall, this study suggests that after cSCI a level of bimanual coordination is retained. While there seems to be a greater reliance on feedback to produce both the reach to grasp, we observed minimal disruption of the more impaired limb on the less impaired limb. This suggests that bimanual movements should be integrated into therapy.

The use of sound during exercise to assist development for children with and without movement difficulties

Purpose. To identify and review the literature on the role of sound in facilitating movement and development. The emphasis was to consider the role of sound during exercise and rehabilitation and to encourage researchers to further explore the role of sound in movement development and rehabilitation. Methods. A review of key and relevant literature was conducted. Data related to the proof-of-concept of a ball emitting broadband sound to enhance motor development in children with and without movement disorders is presented. Results. Analyses of the data indicated an interaction between group and block of training (p ≤ 0.05). Scores indicated that there was no effect of training on the pre- and post-scores for the non-sound group or the control group. However, there was significant effect of training on pre- and post-scores for the group using a ball emitting broadband sound. Conclusions. Preliminary results indicate skill development can be enhanced by the use of broadband sound in balls and further research is required.