نشریه رشد و یادگیری حرکتی - ورزشی
پیاپی 19 (بهار 1394)

There are evidences in both animal and human studies which show that exercise has beneficial effects on the central nervous system and cognition. So، the aim of this study was to investigate the effect of resistance exercise on memory and probable mechanisms of this effect (i. e. neurotrophic factors) in sedentary students. 30 sedentary students (mean age، 23. 8±1. 6 yr) were randomly divided into two groups: control and resistance. After blood sampling and memory test، they continued their exercises for 5 weeks based on the resistance training protocol. In the end، at least 48 hours after the last training session، the memory test and blood samples were collected in order to eliminate the temporary effects of exercises. For analysis of the data، Covariance test and Pearson correlation coefficient were used (P≥0. 05). Results showed that resistance exercises significantly increased memory score (P<0. 05). Although BDNF significantly increased after the exercises، the exercises did not influence the expression of any neurotrophic factors (P˂0. 05). Furthermore، there was no significant correlation between variations of memory scores and variations of expression of neurotrophic factors (P˂0. 05). The findings indicated that exercise can improve memory.

The effect of weight and force is one of the most important factors to organize and perform reaction time (RT) tasks. The elderly are involved in this variable when they gain weight. The present study was designed to examine the effect of limb weight gain on premotor and motor components of simple and discriminative reaction time in young and elderly men. Subjects (16 young and 16 elderly) were asked to perform forearm flexion in response to auditory (simple and discriminative) stimuli. The weight of the involved limb increased (1. 2 kg) in 50% of trials and reaction time and muscle tension were measured by electromyogram apparatus in all trials. The results showed that the main effects of all three factors of limb weight gain، increasing number of stimuli and age on premotor component were significant. The effect of the increased number of stimuli from simple to discriminative was not significant in the motor component (P=0. 77). However، the interactive effects between limb weight gain and age was significant (P=0. 002). These results suggested that those variables that cause variation in limb inertia and generally motor components not only involve motor component but also influence a part of premotor processes simultaneously.

Recently، researches on motor learning have illustrated that learning with effortless process supports learning under psychological stress. Also، contextual interference and practice specificity theories are among those theories which investigate desired practice conditions. The current study aimed at identifying cognitive effort and effortless process based on contextual interference and practice specificity theories. 30 participants were randomly divided into three groups of specificity، random and serial. After the pretest، groups practiced the throwing task for three days. After two transfer tests، subjects were asked to write down the verbal protocol with all details. The results of combined analysis of variance test (3*3) (group*day) revealed the effect of performance progress in practice days and one-way ANOVA tests revealed a significant difference between specificity and random groups during 1 and 2 transfer tests (P˂0. 017). It was concluded that specificity and random groups used effortless and implicit process; therefore، coaches and therapists are recommended to use these two methods to instruct motor skills.

This study aimed at comparing the effect of self-controlled feedback with 100% frequency on motor skill learning in children. 60 children (11. 1±0. 86 yr) were selected randomly and based on their pretest results divided into same three groups of 100% feedback، self-controlled and yoked. In the acquisition phase، subjects completed 120 trials. At the end of the second day، subjects performed a 10-trial block as the acquisition test. After 48 hours، retention test was conducted like the acquisition test. MANOVA with repeated measures on the intra-group factor (trial blocks) was recruited in the acquisition phase and one-way ANOVA and LSD post hoc test was used for the retention phase. The results of the acquisition phase showed the significant effect of blocks (P<0. 05). The findings of the retention phase showed that 100% feedback and self-controlled feedback groups had better results than the yoked group (P<0. 05). Also، in two self-controlled subgroups، the group which received feedback above 50% had better performance. The pattern of these results supported former findings about the effectiveness of feedback in motor learning. In addition، it showed that frequency of feedback had to be high in children during self-controlled feedback.

Mental rotation is the ability to imagine how an object will look if rotated away from the orientation in comparison with the one which is actually presented. That is a component of spatial abilities. This research aimed at comparing mental rotation ability in those with motor and cognitive experiences. The method of this research was causal-comparative and the sample was selected purposively. The sample included 60 boys with a mean age of 17. 17 years (motor experience = 20 subjects in wrestling group، cognitive experience = 20 subjects in computer game group and without motor and cognitive experiences (control) = 20 subjects). Peters et al. Mental Rotation Test (version A) (1995) was used to compare mental rotation. The results of the one-way ANOVA test showed a significant difference between the control group and wrestling group and also between the control group and PC game group (P≤0. 01). There was no significant difference between wrestling and PC game groups in mental rotation (P>0. 05). These findings indicated the positive effects of motor and cognitive experiences on cognitive development (mental rotation).

Physical activity has physiological، psychological، and social positive effects. However، the relationship between physical activities and depression of the elderly in the country is unknown. This study was designed to examine the relationship between physical activity and depression. The statistical population consisted of the elderly of Arak city in 2013 and 263 subjects participate in the study. Data were collected with demographic characteristics questionnaire، Geriatric Depression Scale-short form، and Rapid Assessment of Physical Activity (RAPA) and analyzed with Pearson correlation coefficient، linear regression analysis، t test، ANCOVA test with SPSS-16 software. Findings indicated a significant relationship between depression and age، employment، fall history، economic status، physical activity، education، perceived health (P≤0. 05). Variables of physical activity، fall history in the past year، economic status، and perceived health predicted depression (R2=0. 358; P≤0. 05). Mean score of physical activity in the male elderly was significantly higher than their female counterparts، and mean score of physical activity in 60-69-year-old group was significantly higher than their counterparts in 70-79 and ≤ 80-year-old groups (P≤0. 05). There were no significant differences between age and gender and mean score of depression. These findings emphasize the importance of the effect of physical activity on depression in the elderly.

The aim of the present study was to determine the validity and reliability of the Movement Assessment Battery for Children Test (M-ABC Test) for 6-year-old children of Isfahan city. 306 children participated in the study. Inter-rater reliability of the M-ABC test was estimated using two trained observers with 50 children. Test–retest reliability was assessed using 30 children with a one-week interval. To determine construct validity of this test، explanatory and confirmatory factors analyses were used. Agreement between testers was great with a mean intra-class correlation coefficient of 0. 98. The mean intra-class correlation coefficient of 0. 77 was obtained for test–retest reliability. Three-factor structure of M-ABC test and proper assignment of skills to manual dexterity، ball skill and balance factors were supported for this population. The According to these results، M-ABC test can be applied to assess fundamental skills of 6-year-old children of Isfahan city.

The present study aimed at determining the relationship between learning styles and the effect of random and blocked practices on learning of badminton serve skills. In this quasi-experimental study، 48 female high school students were randomly placed in four groups: 1. convergent learning style with random practice، 2. convergent learning style with blocked practice، 3. divergent learning style with random practice and 4. divergent learning style with blocked practice. After the pretest، subjects went through the acquisition phase under specific conditions of each group and then participated in retention and transfer tests. Kolb Learning Styles Questionnaire (KLSI) and French short serve test and Scott and Fox high serve tests were used. ANOVA was used to compare the scores of the four groups. Findings showed differences among immediate retention، delayed retention and learning transfer (P<0. 05). Convergent learning style and random practice were more effective than divergent learning style and blocked practice to learn badminton serve skill (P<0. 01). Therefore، focusing on the role of learning styles and learning intervention in instructing serve skills gains importance.