نشریه رشد و یادگیری حرکتی - ورزشی
پیاپی 1 (تابستان 1388)

The purpose of this research was to determine the effect of two kinds of diet (zinc deficiency and iron deficiency) on some anthropometrical indexes (body weight and crown-rump length), brain growth and motor function in young rats. Adult male and female albino wistar rats were obtained from the breeding colony of Pasteur Institute, Iran. The female albino rats were mated with normal male rats. After delivery, 40 male rats per group were selected. In order to measure physical and brain growth a special caliper (0.01 mm) and electronic balances (0.0001 g) were used. The instruments for motor function evaluation were Morris Water Maze and Open Field Arena. The data were analyzed by one-way ANOVA and post-hoc analyses were carried out by Tukey’s test (P?0.05). There were significant effects of iron and zinc deficiency on serum iron and zinc level. The results showed that serum iron and zinc concentration after the diet (contrary to the condition before diet) in ZnD and FeD groups were significant. There was a significant difference in some anthropometrical indexes (body weight, crown-rump length) and motor function between ZnD, FeD and control groups but there was no significant difference in brain weight between ZnD, FeD and control groups. The results of this study suggest that sufficient zinc and iron affect motor function as well as physical and brain growth.

The Purpose of this study was to compare the effects of different combinations of mental and physical practices on the acquisition and retention of a motor skill in mentally retarded male students. Subjects were 40 guidance students who were healthy and novice in basketball penalty shot. They were selected randomly and were assigned to 5 homogeneous groups (4 as experimental and 1 as control) based on their pretest scores, IQ and their ability in mental imagery. They exercised for 8 weeks, 3 sessions per week. Kolmogorov-Smirnov test, paired T test, one-way ANOVA and Tukey post hoc test were used to analyze the data. It was observed that all four variations of practice improved their performance, yet the mental practice followed by physical practice group outperformed the other groups. The results suggest that mental practice followed by physical practice results in an outstanding performance in mentally retarded adolescents.

The relationship between relaxation and rhythmic exercises with regard to functional neuroplasticity mechanism is a subject that has been studied in recent researches. The purpose of this study was to investigate the effect of rhythmic exercises on the depth of relaxation in national judo athletes. 30 male athletes of national judo team were randomly selected and divided into three groups: control, experimental 1 (relaxation) and experimental 2 (relaxation and rhythmic), 10 subjects each group. Data were obtained from a three-month period (two 6- weeks, the first 6-weeks relaxation for experimental 1 and 2 groups, the second 6-weeks relaxation and rhythmic exercises for experimental 1 and 2 groups and no exercise for control group) by EMG index. ANOVA and repeated measures tests were used to analyze the data. Findings showed a significant difference in the relaxation skill among groups. On the other hand, exercise periods increased relaxation and rhythmic exercises reinforced relaxation depth. Findings indicated that rhythmic exercises could improve relaxation and its depth.

The purpose of the present study was to compare the effects of two methods of self-modeling and video demonstration of an expert on the acquisition and retention of volleyball serve skill. Participants were 30 students (aged between 12 and 14) who were assigned into two homogeneous groups after the pretest. The self-modeling group (n = 15) watched their performances in the criterion task via a video while the expert demonstration group (n = 15) observed the performance of an expert in the criterion task via a video. Both groups received the verbal cues and instructions. The two groups exercised the task for 4 weeks, 3 sessions per week. Immediately after the 12th session of exercise, a posttest, and 10 days later, a retention test was taken. Paired and independents t test were used to analyze the data. Results showed that both groups improved their performances significantly in acquisition and retention tests. No significant difference was found between the two groups in the acquisition of the skill but the expert demonstration group significantly improved their serve skill in the retention test. It seems that video demonstration of an expert improves students’ learning of volleyball serve skill.

Today physical researchers and teachers consider exercise as a key element to improve motor skills; it is also evident that changeability in practice for retention and performance skills is both proper and effective. The main idea of this study was to evaluate the effectiveness of random and blocked practice methods on retention and performance ability of 12-year-old learners’ passing skills in the Danesh football academy of east Azerbaijan province. For this purpose, a sample of 24 boys were randomly selected and divided into two groups through balancing the means. They were then instructed, trained and finally took tests with reasonable validity and stability (side-pass = 0.86, inside-pass = 0.81 and out-pass= 0.79). The variables were random and blocked practice methods (independent) and retention and performance abilities (dependent). Descriptive statistics were used to classify data and prescriptive statistics to analyze data (T and U-Mann Whitney tests). Findings of this study showed a significant relationship between retention and performance abilities of passing skills in random and blocked methods (P<0.05). Thus, results indicated that blocked practice improves the performance ability of learners while random practice enhances their retention ability.

The purpose of the present study was to investigate mental health status in physical education teachers (PET) and non-physical education teachers (NPET) based on demographic characteristics. 403 teachers consisting of 105 PETs and 298 NPETs from West Azerbaijan province were selected by multiphase cluster sampling method and completed mental health inventory (MHI). The results of the study revealed that PETs scored higher in psychological well-being than NPETs. Male teachers (PETs and NPETs) had higher scores in psychological well-being and lower scores in psychological distress than female teachers. Having a second job was negatively associated with psychological well-being in both PETs and NPETs. Married teachers showed lower psychological well-being than single teachers. Employed teachers had higher scores in psychological well-being than non-employed teachers. Male teachers who had an employed spouse showed lower psychological well-being than male teachers who had a non-employed spouse. No significant association was found between number of jobs, marital status, and employment status with psychological distress.

The Purpose of this investigation was to study the effect of variability of practice and age on retention and transfer of the over-arm throwing accuracy in children. Khalajy and Shafizadeh’s (1383) test of over-arm throwing accuracy was adjusted and used in this study. 48 right-handed female children (16 children in each age group of 4, 5 and 6 years old) were selected voluntarily. Each age group was divided into the variable and constant practice groups according to their pretest scores. The variable group practiced with different target sizes whereas constant group practiced only with one target size. Acquisition phase lasted 3 days; each day included 4 blocks of 6 trials with their right hand. The collected data from acquisition phase, retention test, and immediate and delayed transfer tests were analyzed by mixed factorial ANOVA and Tukey follow-up test. The results showed no significant difference between constant and variable groups in retention test (P>0.05). But in immediate and delayed transfer tests, variable group outperformed constant group (P<0.05). The main effect of age was significant in all phases (P<0.05), so 6–year-old group outperformed 4- and 5-year-old groups but there was no significant difference between 4- and 5-year-old groups. In conclusion, the present study indicated that the age of children affected over-arm throwing accuracy but the variability of practice affected the performance of 4, 5 and 6-year-old children.

The aim of this study was to investigate the effect of computer games on intelligence quotient (IQ), reaction time (RT), and movement time (MT) of adolescents. The statistical population of this study consisted of male high school students (aged between 14 and 18), Restrict 1 in Tabriz city. Two samples (n1=n2=25) were selected purposefully and were divided into two equivalent groups (experimental and control). The experimental criterion was to play computer games a minimum of three days a week for the past six months. The control group played little or preferably no computer games in the past six months. To determine their IQ, Cattle’s intelligence test (Scale 3) and normative tables were used. RT and MT of subjects were measured by appraiser system of RT and MT. Results showed that computer games had a significant effect on IQ (P=0.031), simple reaction time (P=0.017), simple movement time (P=0.019), diagnostic time (P=0.04) and diagnostic movement time (P=0.036). Also findings established that the computer game experience improves IQ, reaction times and movement times.