Developmental Coordination Disorders occurs when development of motor skills has delay, or coordinated movement problems appears. Performance of children with impaired daily activities that require motor coordination is lower than expected by age and intelligence level, and that is not due to physical and psychological illness. The aim of this study was to investigate the possible effects of gymnastics trainings on executive and sensory - motor functions in children with Developmental Coordination Disorder from 8 to 10 years old in Tehran.
Materials and Methods: This research was a quasi-experimental study. Among all patients, 34 children 8-10 years old with Developmental Coordination Disorder in Tehran, that was visited by occupational therapy and rehabilitation clinic in Tehran, available and targeted to selected and randomly divided in two experimental (n=19) and control (n=15) groups. Research tools for screening were Raven intelligence test and the Developmental Coordination Disorder questionnaire. Also, Conner nerves - psychological questionnaire was used to assess dependent variables. Then, the experimental group received an eightweek program for gymnastics locomotor intervention. Statistical analysis was performed by using MANCOVA at significance level P ≤ 0.05 by the SPSS16 software help.
Findings: Significant differences observed between control and experimental groups in all executive variables (F = 492.454ᵃ, P < = 0.05) and sensory - motor (F = 285.683ᵃ, P < = 0.05) functions.
Conclusions: The results showed that gymnastics trainings can improve executive and sensory - motor functions in children with Developmental Coordination Disorder. Therefore, it's recommended that nurseries and schools using gymnastic trainings can help to reduce the Developmental Coordination Disorder in children.

Keywords: Developmental Coordination Disorder, Executive functions, Sensory - motor functions, Gymnastics

Motor development defined as "changes in motor behavior over the lifetime and the process of making these changes". People had been passed various periods of developmental with different rates, that depending on multiple effects of internal factors (biological, motivational, cognitive, and social and ...) and external factors. Children have some movement milestones during its growth like first crawl, sit and walk. Motor coordination is one of the abilities that people earn that by simultaneously interaction with multiple factors. Defect in one of these factors may be the reasons of retardation or delay in the normal process of coordination growth. Although, some children that had a natural appearance was weaker, when their performance of motor skills compared with other children in their age were. These children often suffer from lack of necessary motor skills to perform daily physical activities [1]. According to the latest edition of Diagnostic and Statistical Manual of America Psychiatric, this problem was known as developmental coordination disorder (DCD), which is defined as: Developmental Coordination Disorder occurs when motor skills development has delay, or occurred coordinated movement problems that resulted in performing tasks with error everyday [2]. These people have not problems only in movement, but secondary effects caused by these disorders are the reasons to appearance behavioral and social consequences of being uncomfortable. Hence, in recent years, these abnormalities lead to further investigates in the nature known of it and those handled of more effective intervention in these cases. Due to the problems of children with developmental coordination, disorder has been suggested that locomotor activity may improve cognitive and motor functions of these babies [3]. Thus, motor and exercise interventions can improve a large proportion of motor deficits in these children, early treatment can prevent the next consequences of this disorder, and the public expenditure; these children as well as other peers can easily deal with routine life and schooling. Executive function is a term generally holds all complex cognitive processes that are necessary in performing new or difficult goal - directed homework [4] and includes ability to recess (delay) or inhibition of specific responses and subsequently planned action sequences and maintained a mental representation of the working memory tasks [5]. Executive functions are very important in purposeful motion, in other words in motion control [6]. Thus, existence of substantial difficulties in motor coordination, writing, fine motor, gross motor and existence of failure in perception of time raises the possibility that maybe children with developmental coordination disorder, as well as children with attention deficit disorder/ hyperactivity disorder (combined type) have problems in executive functions. Sensory tasks are depended on sensory systems that weight uses them as sources for getting information from the environment and provide appropriate response and successful adaptation to environmental demands. Human sensory system provides Passage for the brain to receive and interpret stimuli and offering an answer [7]. According to these findings, many areas of developmental disorders in children are associated with Developmental Coordination Disorder in other domains [4,8]. According to some research results, abnormal sensory processing may limit participating in targeted activities such as playing with other people and participating in social activities [9,10]. Comparison Children with movement disorders with normal children indicated that they are more inclined to participate in less diverse activities and motor activities without the fuss and less likely to participate in social activities, especially spontaneous activities [11,12].

According to studies, children with developmental coordination disorder have problems at some meta-cognitive functions, such as mental representation and visualization [2,13], purpose-based movements, setting the scroll speed [14] and new movements [15]. In general, previous studies focused fundamentally on identifying characteristics of children with developmental coordination disorder, and less emphasis on review of underlying mechanisms of etiological neuro-cognitive processes [16]. This Research has shown that cognitive and motor interventions are effective for improving cognitive- motion functions in children with Developmental Coordination Disorder [17].

Most children with DCD do not participate in physical activity. This will cause parents and educators believe mistakenly that these children do not have the ability to perform physical activity, while these children do not participate in activities just for the lack of motivation and laziness [18]. If these children do physical activity poorly than their peers, they become disillusioned very quickly and lose their motivation, which caused a retreat of more exercises. The retreat of activity may ultimately affect children's physical and mental health. Children with DCD are too weak to understand the rules and strategies of the game and in competitive games that need a lot of thinking and coordination. They suffer by movements that require eye and hand coordination, especially in situations where they must respond to moving objects in their environment. Many children with DCD are suffering from muscle stiffness. Due to lack of physical activity. For example, they tend to keep their bodies motionless to maintain posture and balance, instead of doing physical exercises and they keep their joint fixed, instead of moving the elbows, knees, hips and flexible joints. Keeping joints fixed is a cause of vibration in the muscles and the body of the child. This is what makes to show them so awkward. While organized sports activities causes the child to be troubled, there are many activities that children with DCD can have a successful performance, including moderate exercise, like swimming, skating, cycling and skiing. The main purpose of participate in physical activities among children with DCD is creating incentive for them and enhance their ability to participate in physical activity and prevent secondary consequences associated with childhood inactivity. It should be noted that children with DCD might need more time than other children of the same age to increase their skill level. Therefore, they require support and more trainings that are individual. Being exposed to enjoyable physical activities encourages younger children to be more involved, and will causes to increase health and fitness. Many useful activities for children with DCD at early ages perform to enhance body performance in flexibility, balance, strength and endurance. However, these activities encourage young children with DCD; these activities may cause lack of motivation in older children to DCD. Thus, older children with DCD need actions that are more difficult. Some Skills that required keeping balance should be taught to children at different stages. Examples of these types of activities are including martial arts, gymnastics and physio ball [18].

Gymnastics is a sport in which exhibit movements requiring strength, body flexibility, agility, organ balance and coordination. Gymnastics at recreational level is very popular, particularly as physical flexibility trainings. Gymnastics is a sport that will orchestrate the body's movements based on a harmony. In fact, gymnastics can be considered as an art. Due to the proportionality between the Physical and emotional needs for children with developmental coordination disorder and the effects of gymnastics training on individuals, it seems to perform these exercises to be effective in the field of executive and sensory motor functions. In recent years, Ministry of Education has special attention to perform gymnastics in primary schools, especially in the second grade of elementary. Therefore, a law is approved to implement this exercise at schools. However, in our country, according to research studies, research on the effects of gymnastic exercise on executive and sensory - motor functions have not been conducted in children with Developmental Coordination Disorder. Therefore, the purpose of this research is study the effects of gymnastics trainings on executive and sensory - motor functions in children with Developmental Coordination Disorder Researcher is seeking answers the questions that whether do the executive trainings effect on executive functions in children with Developmental Coordination Disorder. Whether do the executive trainings effect on sensory - motor functions in children with Developmental Coordination Disorder?

This study was semi-experimental, cross-sectional and having the functional results on 34 boys with developmental coordination disorder aged 8 to 10 years of age. The sample was selected availability and purposively, from children with Developmental Coordination Disorder society in 2014 that were referred to some occupational therapy and rehabilitation clinics in Tehran (These numbers were maintained to end and was not observed drop test). For entry into the study, the children's IQ was measured by the Raven's IQ test and children in normal area were examined by using the Developmental Coordination Disorder Questionnaire and their scores below 47 and they had no history of heart disease or musculoskeletal injuries were selected for study. Then, they were assigned 19 children in the experimental group and 15 children in the control group randomly.

Tools that used to measure various parameters in this study are including:

Developmental Coordination Disorder Questionnaire Growth coordinate questionnaire is a scale of parental awareness that helps to detect irregularities and Child Development Coordination Disorder. In the Questionnaire, parents want to compare their child's motor function than their peers by using a five-point Likert scale. This standard way is to measure child's coordination activities in daily practices. As reported in 2001, a high level of reliability and validity of this questionnaire have been reported. This new version is suitable for children ages 15-5 years. The questionnaire consists of 15 groups that each group is divided into three distinct factors. The first factor includes items related to motor control and used at the time of the child movement or any other object. The second factor contains quantities of handwriting and great movement, and the third factor is related to the overall organization.

This test was made by Canners in 2004 to assess neuropsychological skills for 5 to 12 years old children such as executive functions (problem solving functions, planning and behavior - emotional organizing), attention, memory and learning, sensory - motor functions, visual- Spatial processing and academic performance in four spectra (don't observer to Severe). Validity of Canners's forms is achieved by using factor analysis method; and discriminant validity of them is endorsed with statistical analysis of the ability of the questionnaire to distinguish them from ordinary people suffering from ADHD and other clinical groups strongly [19].

Doctor ordered allowing exercise, after collecting demographic data (age, height and weight) and examination by him. Before the performing of training program, explained trials to the parents and obtained written consent. Then the children were divided into control and experimental groups by random. Later, Canners's neuropsychological questionnaire provided for their parents to completion. After pretesting from trials, the test group began to doing gymnastic exercises for eight weeks (three one-hour sessions per week). Exercises directed under the guidance of a coach gymnastics in the morning. All used exercises in this study were selected from the gymnast design of the second-grade students of elementary that the suitability of these exercises had confirmed by physical and emotional state doctor of children with Developmental Coordination Disorder. All training programs were performed on the mat, and were taken necessary measures to protect the health of children.

The third session was performed at the end of each session about 10 min, which consists of low-intensity muscle stretching, holding each stretch for 10 seconds, then return the body to rest. Both groups were assessed by Canners's neuropsychological questionnaire for checking the effect of exercise training after the end of them.

Kolmogorov-Smirnov test was used to check the data normality for statistical analysis. In addition, Levine test was investigated for variance homogeneity and then the multivariate covariance test was used to comparing them.

In this section, we first describe the physical characteristics and IQ, the average and criterion deviation between experimental and control groups about executive and sensorimotor functions; and then, the hypotheses test data analyzed by using  MANCOVA test at significance level of α=0.05 and by help of SPSS 16 software (Tables 3 and 4).

Checking of descriptive indicators of executive functions shows the effect of movement gymnastic on the performance of the experimental group. Checks were made on the statistical variables after the test show the reducing deficits and problems during the testing, so that problem average relevant solving Posts / Planning / Organizing is reduced from 2.4857 to 1.3835 and the behavior - Emotional organization is dropped from 2.5524 to 1.2782. This implies the effectiveness of such movement on disorders. In addition, descriptive indicators of sensory - motor function show the effect of gymnastics movements on performance of the experimental group. Checks were made on the statistical variables after the test show the reducing deficits and problems during the testing, so that problem average relevant motor function is reduced from 2.4857 to 1.3835. Also, touch / smell functions from 3.4833 to 1.6974, visual performance are dropped in the range of 2.5111 to 1.2281 and acoustic performance was in the range of 2.6167 to 1.4474. This implies the effectiveness of such movement on disorders. The information of table 5 represents the results of multivariate covariance test (MANCOVA) and shows the difference between the two groups in the domains of executive and sensory - motor functions tests. Based on these results, there is a significant difference (p < 0.05) between these groups in the domain of executive functions. In other words, the differences between the two group scores express that early exercising interventions effect to executive function improving in children with Developmental Coordination Disorder. In view of the square of the beta, we can say that almost all of these changes or improvements are due to interference effects. Also based on these results, there is a significant difference (p < 0.05) between the groups in the domains of sensory - motor functions. In other words, the differences between the two group scores express that early exercising interventions effect to executive function improving in children with Developmental Coordination Disorder. In view of the square of the beta, we can say that almost all of these changes or improvements are due to interference effects. According to pre-test scores as the same diffraction variables (auxiliary), the table 6 results show: the difference between the performance of intervention group and control group in the domains of executive functions subtests is at the p < 0.05 level. In other words, the differences between these two group scores express that early educational interventions effect to executive functions subtests, including solving Posts / Planning / Organizing (The sum of squares of 9.110, F. 242.423 and significant at the 0.00 means a significant difference between experimental groups.) and emotional- behavior organization Organizing (The sum of squares of 13.348, F. 970.980 and significant at the 0.00 means a significant difference between experimental and control groups.). Also the results of this table show, according to pre-test scores as same diffraction variables (auxiliary): the difference between the performance of intervention and control groups in the domains of sensory - motor functions subtests is less than 5 percent. In other words, the differences between the two group scores express that early educational interventions effect to sensory - motor functions subtests, including movement functions, touch / smell functions, visual performance and acoustic performance.

Present study reviews the effects of gymnastics trainings on executive and Sensory - motor functions improving for children with Developmental Coordination Disorder. Analyzing the research findings revealed significant differences between experimental and control groups in measured variables after doing a period of gymnastic exercises. This difference reflects the effect of gymnastics training. Before we get into the discussion of research, it is essential to note that unfortunately, researching on exercise interventions and movement programs on children performance with Developmental Coordination Disorder is very limited and present study is one of the handful researches on movement interventions with gymnastic exercises, according to the research findings and the positive effects of them on cognitive and motor functions in children with Developmental Coordination Disorder, we hope that it will be suitable for future researches. So, explain and discuss about the research findings cite to limited similar researches. Among the problems that children with developmental coordination disorder face to them are defect in executive and sensory - motor functions (Ozuna, 1995). If these children can be helped by exercise can be hoped to treat at an early age and at the same time as are initial or reduce the severity of their disorder and encounter fewer problems in the future. The first hypothesis of this study was the gymnastic exercises have influence in executive functions in children 8 to 10 years with developmental coordination disorder in Tehran. The results showed that the gymnastic trainings effect on executive functions in children with Developmental Coordination Disorder significantly. These research results are compatible with Tsai (2009) and Tesya et al. (2012). In addition, Tsya (2012) saw an improvement in executive function in children by practicing soccer skills. Note that in practice, people need to organize their own behavior, be able to reform the process for skills and decision to move, thus, it appears that exercise can regulate children's behavior, and improve their administrative functions. The second hypothesis of this study was the gymnastic exercises have influence in sensory - motor functions in children 8 to 10 years with developmental coordination disorder in Tehran. As noted above, the results showed that 8 weeks gymnastics training on children with developmental coordination disorder was had on significant impact. The results of this study are compatible with the findings of Tsai (2009) and Rintala et al. (1998) [3,20]. As However, Tsai (2009) during a ping-pong practice was investigated the impact of these exercises on the extent of executive, cognitive and motor function in children with developmental coordination disorder. This study showed that exercise interventions can improve executive, cognitive and motor function in children with developmental coordination [20]. Also Rintala et al (1998) were examined the effects of motor-mental programs on movement skills in children with developmental coordination disorder; And concluded that physical-mental exercise improves movement skills, in particular controlled activities [3]. So we can conclude that although children with developmental coordination disorder are weak than normal children in sensory - motion functions, and also have problem in some movement skills than their peers like driving a tricycle, get off the ball, even daily tasks like taking a spoon and fork, close button dress [21], but what is significant and important is effect of exercise on sensory - motion functions that can help them to overcome learning problems partially.

Suggestions

Due to the variety of equipment in gymnastics, it is recommended that future research should use other gymnastics equipment such as treadmills for more knowing of its effects. Participants in the study were selected from boys. Therefore, it can be used of the girl child in future studies. In addition, future studies should use larger samples to generalize the findings.

Acknowledgement

We thanks from Valliasr Rehabilitation Institute and Allameh Tabatabaee University.

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