نشریه رشد و یادگیری حرکتی - ورزشی
پیاپی 33 (پاییز 1397)

The aim of this study was to evaluate the effect of PST on performance, retention, and transfer under pressure of novice badminton players. 40 novice badminton players were randomly assigned to experimental (20 participants) and placebo-control (20 participants) groups. In acquisition and retention tests, short and long service, toss clear and drop shots were used; in transfer under pressure test, notational analysis was applied. All participants acquired specific badminton skills in 24 sessions over three months. In addition to specific badminton skills, the experimental group received the specific package of PST during 24 sessions (each session 20 min.) while placebo-control group received the same number of sessions about general information on badminton. The results of mixed ANOVA indicated that in all tests, the scores of experimental group were significantly higher than those of the placebo-control group, which indicated the effectiveness of PST on performance and learning of novice male badminton players. The results of this study extended the effectiveness of PST to learning new motor skills.

Coordination is an important part of successful movements in daily life and sports. The aim of this study was to investigate the effect of different levels of cognitive activities on intrapersonal and interpersonal motor coordination in taekwondo athletes (Poomsae). The population consisted of Poomsae male athletes in Tehran city. 30 individual Poomsae athletes and 30 team Poomsae athletes (age range: 17 - 30 years old) were selected by convenience sampling method. The sample was divided into 3 groups: control, easy cognitive activities and difficult cognitive activities. The control group only performed the motor coordination task whereas the cognitive groups performed the dual task. The results of one-way ANOVA test showed a significant difference for two handed (P=0.003) and two legged (P=0.04) coordination in total time factor (speed). Also, there was a significant difference in the error percentage factor for interpersonal motor coordination (P=0.02). In a two by two group analysis, the easy (P=0.003) and difficult (P=0.001) cognitive activities groups in two handed motor coordination and the difficult cognitive activities group in two legged (P=0.02) and interpersonal (P=0.01) motor coordination performed better than the control group. It is suggested that difficult activities should be used in addition to regular physical activities.

The aim of this study was to examine the psychometric properties of Persian version of Sport Injury Anxiety Scale in athletes. The original scale had 7 subscales and 29 items in 5-point Likert Scale. 300 questionnaires were completed by 19-34-year-old athletes (%62.2 male, %37.8 female with the mean age of 24.4 years old) who took part in different sport fields. To assess the construct validity of the scale, confirmatory factor analysis was used. The internal consistency was estimated by Cronbach’s alpha coefficient. Interclass correlation coefficient was also used to examine temporal reliability. The results showed that the Persian version of PSIAS supported the main framework. The validity and reliability of the Persian version of Sport Injury Anxiety Scale with 28 items (item 24 was omitted) were confirmed. According to the obtained results, the Persian version of Sport Injury Anxiety Scale can be recommended as a reliable and valid tool to assess the type and amount of athletes’ anxiety of sport injuries.

The aim of this study was to determine if the reduction of errors during practice facilitates implicit motor learning processes in children. 30 children (meanage =11.33±1.32 yr) threw beanbags with a near-to-far or a far-to-near order, while their vision was occluded. The near-to-far group began the acquisition phase at a distance of 2 m from the target. Then, they practiced the task at a distance of 3 m, 4 m and finally 5 m from the target. Far-to-near group began the practice phase at the distance of 5 m and then moved to 4 m, 3 m and 2 m respectively. Delayed single-task and dual-task tests were administered at a distance of 3.50 m from the target. During the acquisition phase, the ratio of errors made by the near-to-far (errorless) group was found to be significantly less than the far-to-near (errorful) group. No significant intergroup difference was found in the single-task test. The results also revealed that the errorless group performed the task with less errors than the errorful group in the dual-task condition. It was generally concluded that less errors during practicing a motor skill can facilitate the use of implicit motor learning processes in children.

Relaxation is a way of improving performance that can generally be classified as physical and mental relaxation. The mental relaxation technique is often named as the technique of mind to the body since the purpose of these techniques is to provide relaxation through the mind. The aim of the present study was to determine the effect a period of relaxation program (body to mind and mind to body) on the performance of semi-skilled football players. For this purpose, 39 players were selected and divided randomly into three groups: progressive muscle relaxation, creative visualization, and control. Before the interventions, a pretest was conducted by the observational method. In this relaxation program, subjects underwent two different types of relaxation after football training for 8 weeks. Data were analyzed using descriptive and inferential statistics, analysis of variance with repeated measures and one-way analysis of variance. The results showed the significant effect of progressive muscle relaxation and creative visualization on maintaining and controlling the ball, accurately passing, accurately taking the ball from the opponent and overall players’ performance. In addition, the athletes who used progressive muscle relaxation had better performance than those who used creative visualization. In general, the methods of the body to mind and mind to body relaxation can each serve as an independent way to improve the performance of athletes, but the implementation of mind to body relaxation, such as the visualization of creativity, is more effective at skills that require more precision and concentration.

The aim of this study was to compare the transfer of proactive learning between front and back crawl swimming skills in female beginners. 60 students who had registered in elementary swimming course were selected and assigned to four groups (two experimental and two control groups). Experimental groups learned a primary task (front or back crawl swimming) for 10 sessions and then learned the secondary task (front or back crawl swimming; contrary to the primary task). The participants of control groups participates only in secondary task. The results showed that amount of proactive transfer from front crawl to back crawl was 3.06% which was not statistically significant (P=0.977) while the amount of transfer from back crawl to front crawl was 13.45% which was statistically significant (P=0.013). On the other hand, to compare the amount of transfer of these two types of swimming, the results of U Mann Whitney test showed that the amount of proactive transfer of back crawl to front crawl was significantly higher than the amount of transfer of front crawl to back crawl (P=0.001). Therefore, these results support the sequence of back-front crawl swimming instruction in beginners.

The aim of the present study was to examine the effect of combined observational and shadow practices on learning dart throwing skill. 60 female high school students (17-19 years old) who volunteered to participate in this study were selected and randomly assigned to 5 groups after pretest: observational, shadow, physical, combined (observational-shadow) and the control. During the acquisition phase, the practice groups practiced 60 trials of dart throwing skill based on the specific instructions for each group. 10 minutes after the acquisition phase, immediate retention/transfer tests were conducted and after 24 hours of detraining, delayed transfer/ retention tests were carried out. ANOVA with repeated measures (P=0.05) revealed that practice groups had significantly better performances than the control group (P>0.05). Also, physical and combined groups had significantly better performances than the observational and shadow groups (P<0.05). The combined group enjoyed learning equal to physical practice (P<0.05). Overall, the results indicated that combined observation and shadow practices resulted in learning equal to physical practice. These findings suggest that as this practice method can be applied anytime and anywhere with minimum requirements, it can reduce the educational time and costs and even it can be replaced by physical practice under specific circumstances.

Visual impairments as an individual constraint can lead to the lack of adequate visual perception and overshadow children’s all developmental aspects. Therefore, the aim of the present study was to investigate the effect of a course of core stability training on fundamental skills in visually impaired boys. 30 visually impaired children (age range: 5-7 years) were selected by convenience sampling method. After the Ulrich pretest, they were randomly divided into two groups: the core stability training group and the ordinary daily activities. The experimental group participated in the core stability training for 16 sessions, each session 45 minutes. The control group carried out their daily activities. The results of mixed analysis of variance 2 × 2 and Bonferroni post hoc test indicated a significant difference in scores between the two groups so that the subjects of the experimental group outperformed the control group in all locomotors subscales (P<0.05). In general, the results of the study suggest core stability training as a suitable training model to promote fundamental motor skills in children with visual impairment because of increased levels of motivation and enjoyment of physical activity, the development of the children's physical self-concept and enhancement of abdominal and back muscles performance