فهرست مطالب مهدی رافعی بروجنی

The kinematic analysis of elite athletes’ performance is an important method to determine effective parameters of sport performances. The purpose of the present study was to compare kinematic characteristics of the upper extremity in adolescence and adult players in three-step shoot in Handball.

Nine elite adult handball players working in the Super League (23.55 ± 2.69 years) and ten teen handball players (16.4 ± 0.69 years) participated in this study. The pictures related to the final stage of the shoot were recorded three dimensionally and analyzed by a graphic interface in MATLAB software. The data related to the angular position, angular velocity and peak angular velocity and position corresponding to the upper limb joints of athletes, including the wrist, elbow and shoulder were obtained. Statistical data were used for analysis through student t-test for two independent groups with significance level p ≥ 0.05 in order to compare two groups.

There were significant differences between two groups in angular position of elbow joint during extension at maximum angular velocity and linear velocity of the ball at the time of the release.

it seems that other factors than cinematic characteristics such as anthropometric characteristics along with muscle strength in adult are important to get the maximum velocity of ball release.

The purpose of this study was to determine the effects of cognitive-behavioral stress management instruction on the competitive anxiety of karate girls.
Twenty professional karate ‘girls were selected based on the score in Schmidt et al sports anxiety questionnaire had high anxiety levels and a randomized replication design was used to allocate them to the experimental and control groups. They were competing in the superior league of Iran.  Cognitive-behavioral stress management was instructed once a week, and 10 sessions were held. Data about sports anxiety in the pre-test, after the intervention, and three months after the end of the intervention were collected and analyzed.
The results showed that the somatic anxiety, worry, and concentration disruption significantly decreased between the pre-test with post-test and between the pre-test and follow-up.
It seems to raise awareness, stress reduction skills training; cognitive evaluation modification, interpersonal skills development; an increase of emotional expression, and a decrease of social isolation that exists in this program are the causes of the changes that occur.

The purpose of this study was to determine the effect of a selected exercise period on soft and hard surfaces on the static balance of children with autism spectrum disorder. Twenty children with autism spectrum disorder (age 7.8±2.81 years) were selected by use of convenience sampling from Ordibehesht Autism Center of Isfahan. Then, they were matched for age, sex, height, weight and autism index and assigned into two groups of 10 persons whom exercised on a soft surface and hard surface. They participated in a period of selected balance exercises for 24 sessions (three times a week). Static balance of these children was evaluated in the pretest and post-test by assessing the amount of displacement of the center of pressure in the anteroposterior and mediolateral directions while standing on the Foot Scan for 18 seconds. To analyze the data, the mixed (2 × 2) variance analysis was used (p <0.05).  The results showed that static balance with open eyes of both groups improved significantly after the intervention. However, there was not significant difference between the two groups of exercise on the soft and hard surfaces. Exercise on surfaces with different stiffness improves the balance of children with autism spectrum disorder by reinforcement of the proprioceptors.

Stuttering is known as the most prevalent mental speech disorder. Studies indicate a direct relationship between stuttering and poor attention control. People with stuttering have difficulty concentrating and adjusting attention. Because of difficulty in stuttering treatment as the child grows and ages, it is essential to follow up on this disorder in childhood. Scientists use various therapies, including cognitive therapy, art therapy, and hypnosis, to treat stutterers. Numerous studies have supported the benefits of exercise in controlling cognitive processes, including selective attention, planning, organization, flexibility, and retention associated with working memory.  Recently, researchers have recognized that instead of using a simple aerobic exercise, using physical activities with a cognitive approach is more beneficial for cognition development. In the present study, a racket sport, ping pong, is used for intervention. Research has shown that ping pong exercises as a physical and cognitive physical activity can improve attention and concentration. Therefore, the present study aimed to study the effect of a ping-pong training session on selective attention and stuttering severity in children with stuttering.

 The present study was a case study. In this study, the A-B-A-B design was used. Two boys and a girl with the stuttering disorder ranged 6 to 7 years old were selected. The code of ethics (IR.UI.REC.1398.034) was obtained from the Scientific Research Committee of the University of Isfahan, and the childrenchr('39')s parents completed the consent form. The intervention consisted of 24 sessions of ping pong exercises intending to improve selective attention. Selective attention and stuttering intensity were assessed by the Stroop test and stuttering intensity scale, respectively.  Stroop and stuttering intensity tests were used at intervals of one day between (5 times) to achieve childchr('39')s first baseline (A). Then, the children entered the first intervention stage (B). Intervention time for each child was 16 sessions of ping pong exercises, three sessions a week. In the second stage, the intervention was stopped for one month, and only Stroop and stuttering tests were taken from children (Achr('39')). Then, in the second stage, the intervention was performed again for one month. After that, in the second intervention phase, one month of the intervention was performed again, in which the subjects practiced for eight sessions (Bchr('39')). In this phase, participants entered the training process, and after each training session, the mentioned tests were retaken.

After analyzing the data, the results of the present study showed that the percentage of non-overlapping points (PND) of the subjects for selective attention was 18%, 75% and, 66%, respectively, and the percentage of non-overlapping points (PND) for stuttering intensity, respectively 72%, 68%, and 75% were obtained. Since the higher, the percentage of non-overlapping data, the more confident the intervention can be considered effective. So, according to the obtained results, ping pong exercises were effective on selective attention and the severity of stuttering in children.

Findings of the present study revealed that ping pong exercises were effective in improving selective attention. According to previous studies, ping pong exercises require complex physical coordination and adaptation to constant change, so hard-working cognitive processing requires high cognitive control, decision speed, and especially attention and concentration to improve cognitive functions. In addition, the results of the present study showed that ping-pong exercises were also effective in reducing the severity of stuttering in children. Besides, the research has indicated that there is a relationship between speech mastery and attention. Ping-pong exercises may have reduced stuttering in children by improving selective attention and inhibitory control. The present study is a single case study. It is suggested that in future research, researchers conduct a similar study with a larger sample size so that the results are generalizable.

It is well documented that competition can affect performance in sports. However, investigators have not studied the effects of types of competition on learning sport skills. The main purpose of the present study was to compare theeffects of individual and group competition on acquisition and retention of volleyball serve. A total of forty male adolescents (age ranged from (16 to 18) were divided into either an individual or group competition groups. The participants were novitiate in volleyball. Based on the task pre-test scores, participants were required to exercise the task either in individual or group competition environments. The AAHPERD volleyball serve test (1984) was used to measure the task performance. The participants of the two experimental groups exercised the task for 10 sessions. Pretest, acquisition tests and retention tests were taken at pre intervention, acquisition, and post intervention times respectively. For analyzing data, independent sample t test and repeated measures analysis of variance were used. The results showed that the performance of the two groups was found to be similar across acquisition phase while a between group significant difference was found at immediate and delay retention phase in terms of the skill performance. The results also showed that the performance of group competition participants was better than the performance of individual competition participants. We suggest that teachers and instructors use the results of the present study to decide on the type of competitive environment for teaching volleyball serve to adolescent male students.

The purpose of the present study was to determine the effect of pairing the personality characteristic of competitiveness, non-competitiveness and training environment in observational practice on acquisition, retention and transference of dart throwing. 60 girl students of ninth grade in high school in age range of 12-15 years were selected by accessible sampling and based on their scores in Gill and Deeter Sports Orientation Questionnaire. They were put in four groups of competitive with observational practice of competition environment, competitive with observational practice of non-competition environment, non-competitive with observational practice of competition environment and non-competitive with observational practice of non-competition environment. After pretest subjects practiced four weeks and two sessions held in every week (two observations for each session) of the intended environments. Immediately after the observational practice period, acquisition test was performed for all four groups. The delayed retention and transference phases were a week after acquisition. The data was analyzed using a data covariance analysis method. There were significant differences between competitiveness and non-competitiveness subjects in competitive and noncompetitive environment in retention and transfer tests. The mean of scores were better in subjects with the same personality characteristics with environment situation. According to interaction view, when the level of competitiveness and exercise environment competition level are in a correct and positive interaction, the best level of performance will be achieved.

Lifestyle improvement is one of the main strategies to increase treatment persistence in breast cancer survivors. The purpose of the present study was to determine the effect of a light-intensity physical activity program on Socio-cognitive factors that affect sedentary behavior and lifestyle in breast cancer survivors in Isfahan city. Twenty-four female breast cancer survivors were recruited via convenience sampling and randomly assigned to experiment and control groups (12 subjects for each group). Both groups were assessed using Busschaert’s context-specific sedentary behavior questionnaire and the Miller-Smith Lifestyle Assessment Inventory before and after the intervention. The light-intensity physical activity program was conducted for one month in the experimental group based on Australia’s Physical Activity and Sedentary Behavior Guidelines for Adults. Data were analyzed using descriptive statistics including mean and standard deviation and inferential statistics including ANCOVA and MANCOVA with a significance level of 0.05. There was a significant difference between the two groups in lifestyle and Socio-cognitive factors affecting sedentary behavior (except for the sedentary behavior modelling) (p = 0.001). It seems that performing light physical exercises may improve the lifestyle and Socio-cognitive factors affecting sedentary behavior by changing key factors such as motivation and intrapersonal relationship in breast cancer survivors.

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.

To create more efficient learning environments, the learner’s role and his/her influence on the learning process should be considered. The aim of this study was to determine the way self-controlled practice affected performance and learning of motor patterns. 60 female undergraduate students (mean age = 20.73 yr., SD = 2.98) were randomly assigned to four groups that ordered self-controlled practice or three yoked-to-self-controlled. In the acquisition phase, the self-controlled group was told they could choose whichever of three motor patterns they wanted before they practiced each trial. Each self-controlled participant’s practice schedule was served as the predetermined practice schedule for each corresponding participant in the yoked control groups. The yoked control participants practiced the tasks with high, low, or no (classic yoked-control) variability. The results showed that the self-controlled group performed the tasks faster than the other yoked control groups in both the acquisition phase and the retention tests. The findings suggest that if the learners are allowed to choose the sequence of practice in multiple motor skills, this would have facilitating effects on their performance and motor learning.

The purpose of the present study was to determine the effect of PETTLEP imagery and physical practice of choice reaction time on simple and choice reaction time and the pre-motor and motor areas of simple and choice reaction time. Based on mental imagery ability that measured by Vividness of Movement Imagery Questionnaire 2, 26 non-athlete girl students (age 21.23±1.2 years) were chosen purposefully and divided in two groups, each comprising 13 individuals to perform PETTLEP mental imagery exercise and physical exercise of reaction time. The Simple and choice reaction time of subjects were recorded in pre-test and after 10 sessions of 10 repetitions training by researcher-made reaction time device. In the post-test, in addition to recording reaction time, pre-motor and motor areas of reaction time in both simple and choice situations were recorded using electromyography. For analyzing data, the statistical methods of mixed two- way ANOVA and t-test were used in SPSS 23 software. The results showed that after the intervention, the simple (P=0.004) and choice (P=0.001) reaction time was reduced significantly in both groups. Also, there was a significant difference between the two kinds of exercise in simple reaction time (P=0.045). However, there wasn’t any significant difference between these two kinds of exercise in terms of reducing choice reaction time. Therefore, it can be concluded that by solving cognitive problems and reducing the time needed for information processing, PETTLEP imagery and physical exercise help to reduce reaction time.

The purpose of the present study was to determine the effects of physical and observational practices on electromyography features of active muscles in high badminton serve. 30 nonathletic girl students (age 18 – 24 years) randomly assigned to tree physical, observational and combination groups after pre-test. Surface electromyography was done from biceps, triceps and middle part of the deltoid, in the observational group during and in all groups before and after 4 sessions practice. A mixed model of variance analysis was used to analyze data. There was significant decrease between pre and posttest in activity time, mean and peak normalized activity of biceps and deltoid muscles. At neurophysiology point of view, observation will activate a mirror mechanism that leads to facilitation of movement for imitating act.

The aim of the study was to compare the electrical activity pattern of major muscles involved in handball triple shooting in two groups of adolescents and adults. Ten adolescent elite handball players playing in national club league (16.4 ± 0.69) and 10 adult handball players (23.55± 2.69) participated in this research. They performed triple shooting æ assuming in a match situation and electrical activity of the Biceps brachii, Triceps brachii, pectorialis major muscles and three anterior, middle and posterior parts of deltoid was recorded using surface electromyography. Parameters related to the muscular activity pattern, including time, peak, action amplitude and contraction sequences were obtained. The results of t-student statistical test for two independent groups (p≤ 0.05) shown that there were no significant difference between time, peak and electrical activity amplitude variables between groups. It seems the factors such as experience in adolescent athletes, better utilization of muscle and being close to the end of puberty makes no difference between adolescents and adults.

The main purpose of the present study was to investigate the effects of 8 weeks of horseback riding on social interaction of children with autism spectrum disorders (ASD). The study included 25 eligible (diagnosed ASD, school age) children with ages ranging from 5 to 16 years whom they assigned to an exercise (n=11) or a no-exercise control group (n=14). Participants of the experimental group received horseback riding skills four times per week for 8 weeks (32 sessions). Social interaction was assessed at baseline and two days’ post-intervention in both groups. Results showed that horseback riding significantly improves social interaction in the exercise group. The participants of the control group did not show significant changes in their social interaction scores. The findings of the present study indicate that instructing horseback riding to children with ASD improves social interaction of children with ASD.

A growing body of evidence confirms that regular physical activity leads to multiple physiological and psychological benefits. The purpose of present study was to assess the effect of participating in health stations of Tehran municipality on general health، body composition، blood sugar and pressure of participant citizens. A total of 470 individuals including 197 women and 273 men (mean age 51. 9±12. 8 years) were selected using random cluster sampling from 22 regions of Tehran’s health stations. General Health (General Health Questionnaire (GHQ-28))، Body fat، body mass index (BMI)، waist to hip ratio (WHR)، blood glucose and blood pressure were measured at baseline and eight weeks later. Findings showed that body composition factors، blood glucose (pretest: 129. 45±35. 64 and posttest: 127. 85±15. 12 mg/dl) and blood pressure (pretest: max 129. 9±4. 7; min 79. 7±3. 7، posttest: max 124±4. 2; min 75±4. 1 mmHg) were significantly decreased in some regions of Tehran municipality (p<0. 05). There were significant improvements in all subtests and general health in municipality regions (p< 0. 05). Participating in exercise stations affected body composition factors، blood sugar and pressure. In general، participation in exercise stations is effective in improving health level of participant citizens.

The precise control of arm kinematics and kinetics as well as interaction of the arm with the external word, is an essential condition to perform skillful motor actions. Gravity has significant effect on spatial orientation, proprioception, displacement, start and stop of hand movements. The purpose of this research was to study the effect of movement direction variation in relation to gravity on generalized motor program recruitment in fast single joint elbow movement by use of surface electromyography. Fifteen volunteer students (mean age 24.8± 3.8 years) without sensory motor impairments participate in this study. Ninety percent of full range of motion at the elbow joint was used as goal degree. Subjects asked to do aimed elbow flexion as fast as possible in seven different direction in relation to gravity. While they were performing movements, surface electromyography was recorded from biceps and lateral head of triceps muscles. Relative timing, relative activity and sequence of contraction were derived from RMS. Data were analyzed by using repeated measure variance analysis. Muscle activation patterns were different in three positions from rest. There were significant difference between relative activity (p<0.001) and relative timing (p<0.003) in some positions. In fourth position, sequence of muscle contraction was different in seven subjects. It seems that change in movement direction in relation to gravity is one of effective parameters in movement planning and execution and it can recruit different generalized motor program.

The purpose of this research was to study the effect of change in movement direction in relation to gravity on control strategy and rate of electromyography rise in fast single joint elbow movements. Fifteen right handed men without any history of neuromotor injury (mean age of 24.8 ± 3.8 year) participated in this study. We asked of subjects to perform elbow flexion as fast as possible in seven different directions in respect to gravity with 90 percent of full range of motion. While they were performing movements surface electromyography done from biceps and lateral head of triceps. By dividing electromyography activity range (peak activity minus rest activity) on time range of activity (time of peak activity minus time of onset) slop of receive to peak of electromyography or rate of electromyography rise computed. Data analyzed by use of repeated measure intracase variance analyze (P 0.05). There were not any different in biceps muscle but rate of electromyography rise had significant different between movement in horizontal plane around vertical axis with movement in sagittal plan around frontal axis(against gravity), sagittal plan around frontal axis(with gravity), supine and dangle positions in triceps muscle. Movement direction in relation to gravity cause to use simultaneously of speed sensitive and speed insensitive strategies in fast single degree of freedom elbow flexion and had significant effect on rate of electromyography rise in triceps muscle.

Substance abuse, violation and sexual behavior are the main reasons of fatality in adolescents and the youth. Most risky behaviors including cigarettes, alcohol, drugs and unsafe sexual contacts occur under the age of 8. Traditionally, sport is regarded as a means to encourage and develop healthy behaviors and a factor to protect and prevent risky behaviors. The present study studied 406 students including 27 male and 35 female students to compare the vulnerability of male and female athlete and non-athlete adolescents to risky behaviors such as smoking, drugs and alcohol. Iranian Adolescence Risk-Taking Scale (IARS) was used to measure the risk taking (Zadeh Mohammadi & Ahmadabadi, 2008). Those adolescents who have been a member of athletic teams had higher mean in subscale ‘drinking alcohol’. Those athletes who participated in provincial competitions and higher levels, those who engaged more than three sessions a week in sport teams and those athletes who attended sport camps had a higher mean. Also, there was no significant difference between individual and group sports. When explaining the higher levels of risk-taking in those who were members of athletic teams and clubs, factors such as duality, and the difficulty in playing the role of a student and an athlete simultaneously, camp condition, lack of sufficient control over members’ behaviors except when they are playing, peers’ collective norms, normative pressure to conform with various expectations of the team, lack of scientific attitude towards school athletic organizations in Iran, and concurrent influence of personality features like sensation and novelty sought in tendencies toward sport and risky behaviors can be taken into account.