The effect of selected exercises on reaction time and posture control of 7-8 year old boys with developmental coordination disorder (DCD)

Master's degree

Motion behavior and sports psychology

Developmental coordination disorder is used to describe children who have difficulty in performing some movement skills and suffer from the necessary competence to deal with their daily movement needs. The purpose of this study was to investigate the effect of selected exercises on the reaction time and posture control of 7-8 year old boys in Ahvaz city. Among all the first and second grade students of one of the schools in Ahvaz city, 20 children were diagnosed with disorders using Bruyninx-Ozertsky test and developmental coordination disorder list, and they were divided into two experimental (10 people) and control (10 people) groups. The research method was pre-test-post-test, where the experimental group performed selected exercises (combination of aerobic exercises and rhythmic games) for 8 weeks. And the control group did not receive any training or intervention. Dependent t-test was used to investigate the effect of training, and multivariate analysis of variance and one-way analysis of covariance were used to determine the difference in groups. The findings show the effect of selected exercises on two variables of reaction time (in all conditions) and posture control (p?0.05). Therefore, the experimental group showed better performance as well as improvement in the disorder and showed the positive effect of these exercises on children.

Keywords: developmental coordination disorder - reaction time - postural control                                                                                                                                                                                                                                                                  The first chapter

Introduction and introduction

Research

1-1. Introduction

Growth is the changes that all humans face during life. Such changes are obtained as a result of age, as well as people's experiences in life and genetic potential, and they are obtained from the mutual influence of these three factors on each other at any time, so growth is a mutual process that leads to changes in behavior throughout life (Heywood [1], 1993). Motor development is a continuous and sequential process during development in which skills change from simple to difficult, from unorganized to organized, and from unskilled to skilled throughout life (Heywood 1993). As children gradually develop coordination with physical growth and age, a toddler who shows walking in the initial movements does not have much balance in the early stages, but with the passage of time and age, this weakness is removed and this basic skill is performed correctly (Bernstein[2] 1967). Developmental Coordination Disorder [3] (DCD) is a term proposed by the American Psychiatric Association to describe children who had difficulty performing some motor skills and suffered from the necessary competence to deal with the motor needs of their daily lives. Based on the diagnostic criteria presented in the revised text of the Diagnostic and Statistical Manual of Mental Disorders [4] (DSM-IV-TR), this association has specified the criteria, criterion A: the movement coordination of this group of children is significantly lower than their age and intelligence ability. Criterion B: These coordination problems have certain negative effects on their academic progress and daily life activities. Criterion C: But this disorder does not cause a specific medical condition or extensive developmental disorders (American Psychiatric Association [5], 2002). There are different statistics about the prevalence of this disorder. So that Lingam and his colleagues[6] (2009) have estimated the prevalence of this disorder at 1.7%, while Misiona et al.[7] (2008) reported that 5-6% of primary school children suffer from this disorder. Despite the differences in prevalence statistics, all international estimates generally agree on a higher prevalence in boys (American Medical Association, 2002; Lingam et al., 2009). In this disorder, movement problems such as developmental delay, balance disorder, perception disorder, physical inexperience and weak movement coordination and to some extent neurological disorder have been reported (Gives[8], 2005).In addition to motor coordination problems, children with developmental coordination disorder have other problems such as learning problems, speech problems, and language problems. It is believed that fifty percent of children who have learning problems also suffer from developmental coordination disorder. In many cases, the child grows up with a lack of self-confidence and low self-esteem (Lynch et al. [9], 2012). Considering that the efforts of specialists to improve the performance of children with coordination disorder and considering the high percentage of people with this disorder (one out of every 10 children), the present research is the percentage that investigates this important issue.

1-2. Statement of the problem

Movement is one of the most important aspects of human life. If they do not have the necessary skills in daily life movements, they will not have the proper efficiency and the normal process of life will be disrupted. Children and adolescents with developmental coordination disorder show reluctance in activities that require physical and motor response, and a kind of intolerance, failure and low self-esteem are observed in them (Missiona, 2002). Developmental coordination disorder is an injury, immaturity or movement disorder, according to this, a person may face problems in the way of speech, eye movements, perception, thinking, special learning problems, personality and fixed behavior (Archibald[10], 2008).

Although developmental coordination disorder includes a wide range of features, but the distinctive feature of this disorder is that children with motor learning problems are able to do everyday tasks. themselves are not acceptable (Mendich et al. [11], 2003). A child with this disorder may have problems with self-care tasks such as eating with a spoon and fork, school tasks such as handwriting and drawing, and organizing their work (Guin [12], 2003). Successive failures in performing these actions cause the child to avoid participating in these skills (Smith, [13] 2003). Developmental coordination disorder occurs when a child's motor ability is significantly lower than expected for the child's age and intellectual ability (American Psychological Association, 2002). In the early stages of life, children with developmental coordination disorder have difficulty sitting, crawling and walking. Because improvement on age-related tasks can also be below average, they may not be able to tie a shoelace, play a ball, or complete a puzzle (Hook [14], 2002). It should be noted that a young child with developmental coordination disorder may be clumsy and very slow. Children with developmental coordination disorder have problems in the visual and sensory-motor system, balance and reaction time widely. The primary cause of the deficit is related to visuospatial processing, sensorimotor perception, and the nervous system (Wilson, McKenzie [15] 1998). Postural control comes from the confrontation and interaction of a person with the task and the environment and is defined as a process in which the central nervous system produces the necessary muscle patterns to adjust the relationship between the center of mass and the level of support (Netz[16], 2005).

Reaction time is the time interval between the unexpected presentation of the stimulus and the start of the response. Reaction time is the sum of three stages of information processing, and it is the time required to identify the stimulus, select the response, and initiate the appropriate response (Schmidt [17], 1991). It is worth mentioning that children with developmental coordination disorder are likely to face other disorders as well. Weakness in postural control and reaction time has long been implicated as one of the movement problems in developmental coordination disorder. Based on a critical review of relevant literature and some findings, we argue that the importance of poor reaction time and balance in children with DCD has been underestimated (Missiona, 2008). Not much research has been done on the effect of physical activity on the reaction time and balance of these children. As Shirley [18] (2013), studied the effect of Taekwondo training in controlling balance and maintaining stability in children with developmental coordination disorder. He concluded that the children who did Taekwondo exercises for 3 months had better balance than the control group.

Rainer [19] (1998), Smith [20] (1991) and Henderson [21] (1992) in their research on the reaction time of children with developmental coordination disorder compared to normal children concluded that these children have a weaker reaction time than normal children.