فهرست مطالب مهدی شهبازی

Athletes may perform weaker than their own skill level (choking), when are being watched by others (monitoring) or receive a reward if a specific goal is achieved (outcome). The purpose of this research was to study the effects of monitoring and outcome pressure on cognitive decision-making task in table tennis athletes. 30 elite athletes took part in this semi-experimental study in a within-group design and performed the task under one 15-trial block of low pressure and two 15-trial blocks of monitoring and outcome pressure in two separate days. Subject did the task in a “take the first” heuristic paradigm. To measure competitive anxiety level under pressure, Competitive State Anxiety Inventory-2, And to measure propensity to self-focus behavior, Decision-specific Reinvestment Scale was used. Analysis of variance with repeated measure Results showed that under both high pressures, decision making task (p ≤ 0/05). The results of regression revealed that the propensity to reinvestment couldn’t predict changes in decision making under pressure. Distraction approach provides the better description of choking under pressure.

Combining self-controlled and imposed levels of task difficulty during training seems to be better than completely self-controlled conditions. This study aimed at determining whether self-control of task difficulty affects skill learning during the early and late practice stages. For this purpose, 48 novice of high school students with a mean age (17.5 ± 1.75) years were randomly divided into four groups including complete self-controlled, self-controlled at the early, self-controlled at the end and paired. In the acquisition phase, which includes 100 trails,the self-control group was informed that they could choose and practice any of the preset distances from the target (1/5, 3, 3/5, 4, 4/5, 5 m) before each trial during the acquisition phase. The task difficulty was either self-controlled or imposed to the participants in the two phases of the acquisition session. The accuracy score of basketball throwing were analyzed by mixed variance analysis with repeated measures in acquisition and retention and transfer tests. The results showed that self-control of task difficulty improves the compared to the paired group (P=0. 001). Secondly, the performance of self-control of task difficulty in the early practice group was better than self-control of task difficulty in the end practice group (P=0. 001). Third, accuracy in the self-control of task difficulty in the early practice group was significantly better than self-control difficulty group and the paired group (P=0. 001). In general, the benefits of self-control of task difficulty were justified using the challenge point framework, the information processing perspective and cognitive perspective.

Instagram has created a new arena for celebrity activity and changed fan patterns. Today, visual self-representation is the most content of social media. In this situation, celebrities create a new identity for themselves.In this study, the survey method was used to collect information and the questionnaire technique was used. Also, in the theoretical part, the approaches of "representation of celebrities in social networks", "lifestyle and celebrity", "online socialization and celebrities" and "celebrity visual communication" have been used.The results of the research show that the interaction of fans with celebrities at the Para-Social level is more than the interaction at the level of identification and worship. Para-Social Interaction (PSI) as a new issue can affect people's self-image concerns. In such a way that the worship of famous people and Para-Social Interaction (PSI) are effective in this field. Approximately 47% of users are attracted to celebrities. In such a way that in addition to being interested in Para-Social Interaction (PSI) with celebrities, in the abstract dimension, they imitate the values and attitudes of celebrities, and in the behavioral dimension, they worship and imitate the lifestyle of the popular celebrity. The present study shows that the most important content production by celebrities for users is: "sharing and sending interesting updated images", "publishing videos and images of the celebrity's professional activity", "publishing heartfelt messages for fans in the form of images or messages" and "publishing works of fans on their Instagram page".

Optimal performance of complex Forehand stroke needs coordination between postural adjustment and focal movement. the purpose of this study was to investigate the relationship between onset time and magnitude of Anticipatory Postural Adjustment (APA) and constant and variable error of Table Tennis Forehand stroke among skilled and novice players. For this, skilled (n=10) and novice (n=10) participants, perform Forehand stroke under Coincident Anticipation Timing (CAT) paradigm and EMG of selected postural muscles were simultaneously recorded. The results of investigating the EMG data showed that in all postural muscles, APA was occurred before focal movement initiation. In addition, the results of two way MANOVA test showed that in comparison with novices, skilled players had higher accuracy and lower variable error in their performance (P<0.05). Also, the result of Pearson moment correlation test revealed that among skilled players, both early onset time and greater magnitude of APA correlated with higher accuracy (P<0.05); however, only the APA’s onset time correlated significantly with both accuracy and variability of novices’ performance (P<0.05). Lower variable error in skilled players’ performance in comparison to novice counterparts and yet lack of correlation with onset time and magnitude of APA, probably indicates the consolidation of internal models as a result of practice and long term experience of skilled players in that sports skills.

The purpose of this research was investigating the effect of handball nonlinear pedagogy on motor creativity of Robat-Karim female students. In this research, first, 30sixth grade students (experimental and control groups) were selected by available sampling strategy, but unfortunately, with the spread of Covid-19 and increasing concern of parents about their children getting sick, many subjects were withdrawn, and only 8people (11-12 years old) remained. The research method was semi-experimental and practical in terms of purpose, which was carried out using a pre test-post test design. The research tool was Burch's motor creativity test including 4stations (throwing, balancing, locomotion and carrying the hulahoop). The research subjects were beginners and had no experience playing handball. In order to familiarize with the basic handball skills, they were trained for 8weeks, 2sessions per week, and each session 60 minutes. Then they entered the nonlinear pedagogy process and played handball for 8weeks, 2sessions per week, and each session 60 minutes, using the principles of small sided games (changeing the number of players). The results of Wilcoxon, MANOVA and univariate ANOVA with repeated measures showed that nonlinear pedagogy has no significant effect on the motor creativity. In fact, the nonlinear approach could not provide a dynamic context for direct perception and developing motor creativity in changing conditions. In other hand, this approach has been affected by subject staying at home, becoming inactive, and the dropping out, and it is suggested that other constrains are also Interfered and their effect on students' motor creativity is studied.

The purpose of present study was to test the effect of contextual interference and self-regulation on the transfer of volleyball services (underhand and windmill service).

Participants were 39 male students (20-25 years old) were randomly assigned to one of three groups (blocked, random and self-regulation) and performed total of 40 trials of volleyball service each session (6 sessions). The blocked group practiced 40 trials of one service each session but the random group randomly practiced both services. In self-regulated group, the type of services in each session was determined by subjects. The transfer test was conducted one week after practice period in 5 trials. In order to analyze the data, the one-way analysis of variance and the Tukey’s post hoc tests were used.

The comparison between the pre-test and transfer test showed that the difference between blocked and random groups was not statically significant. The  self-regulation group had higher transfer scores compared to blocked and random groups.

The results of present work support the contexuual interference affect but it’s not significant. Self-regulated practices involve the subjects in learning processes. Also, with his method, they participate more activity in determining the characteristics of the exercise. These factors lead to the improvement of learning and better performance.

This study aimed to investigate ego-depletion, attention control, and decision-making in proficient female soccer players. Utilizing a quasi-experimental design with an applied objective, the research was conducted intra-group using a pre-test-post-test methodology. The statistical population comprised proficient female footballers who competed in the Premier League of Tehran Province. This study involved forty proficient female football players, with an average age of 23.09+2.03 years, who had at least eight years of competition experience. The samples were arbitrarily divided into two groups—ego-depletion and non-ego-depletion—using convenience sampling. The data were collected using the personal information questionnaire, General Health Questionnaire, Stroop, and the Decision-making tool. The ego-depletion group’s self-control strength was diminished in two cycles of eighty trials through the prior task, which was the Stroop inconsistent task. They executed a computer-based decision-making task under distracting conditions, which comprised 180 images depicting various football scenarios. The data analysis was conducted using SPSS-21 software and a mixed ANOVA with the SYNTAX command. The results showed that the ego-depletion group made decisions with significantly slower speeds and reduced accuracy (P<0.001). In contrast, the non-ego-depletion group demonstrated a statistically significant improvement in accuracy (P=0.003) but a considerable decline in decision speed (P<0.001). Overall, one could contend that mental fatigue-induced ego depletion undermined the capacity for self-control, which consequently compromised the decision-making abilities of the participants.

Training in a certain skill not only culminates in better motor performance but also leads to neural adjustments and regulations in different brain regions.

The present study aimed to psychologically assess event-related motor potential in motor-related cortical regions during simple and complicated tasks.

The current research was of a semi-experimental type with a single-phase post-test design without a control group. The participants of the present study consisted of all 20-32-year-old right-handed male table tennis players in Tehran, in 2019. A total of 8 samples were selected via convenience sampling. Data were collected at the National Brain Mapping Laboratory. Annett Hand Preference Questionnaire (1970), Ocular Dominance Testing Card (1910), the Newgy Robo Pong Model 2050 Digital Table Tennis Robot, and the Specific Test for Table Tennis Stroke (2016) were used to record speed from Radar gun, and cameras and judges’ scoring were also used to measure accuracy. Moreover, the two-way analysis of variance (ANOVA) statistical test was employed to assess the differences in two levels of task complexity in SPSS software version 24.

The results showed that the motor potential in the primary motor cortex region had a greater range in the simple task than in the complicated task (P=0.012); however, the premotor (P=0.008) and the posterior parietal cortical regions (P=0.026) of the complicated task had larger ranges than the simple task.

According to the results of this study, the motor potential range is dependent on the task complexity level. Therefore, it is suggested that tasks with different complexity levels be taken into account in investigating event-dependent potentials.

The current study aimed to investigate the relationship between the performance of children in motor coordination skills and their ability in cognitive and affective empathy. The participants contained 45 students aged 7-9 years from Tehran elementary schools. Movement Assessment Battery for Children-second edition (MABC-2) was used to asses motor coordination skills including manual dexterity, aiming, catching, and balance. Moreover, cognitive and affective empathy were evaluated employing Griffith Empathy Measure (GEM). Univariate and multiple linear regression revealed that manual dexterity and balance were positively and significantly correlated with affective and cognitive empathy explaining 7 and 11 percent of their variance, respectively. Moreover, manual dexterity was positively and significantly correlated with general score of empathy, while not controlling for the other variables. Monitoring motor coordination skills, fine motor skills in particular, seems necessary to prevent deficits in development of social skills such as empathy.

A few studies have examined the interactive self-control effect on the type of self-modeling feedback. The purpose of this study was to determine the effect of providing different strategies of self-control feedback through self-modeling on learning of Lay-up shot basketball skill. For this purpose, 60 right-handed 11-13 years old male beginner students were selected through available sampling. Then they were divided into 4 groups randomly. One of the groups between the blocks and the other group before training session defined to get the type of self-modeling feedback (best performance or overall performance in Lay-up shot basketball skill). For each of these groups, the yoked group was selected. The training program was conducted for 6 sessions for two weeks. Pretest, retention and transfer test were made in 12 attempts. Results showed significant effect between pretest with retention and transfer tests scores. Also, there was significant difference between the self-control feedback before sessions and the self-control feedback between the blocks groups and their yoked group in the retention and transfer tests (P≤001), While between the yoked groups did not had any significant difference. These results indicate the greater effect of self-control feedback during sessions, which emphasizes the greater autonomy of learners as one of the psychological needs for learning optimization.

The purpose of this study was to investigate the effect of play at home, as proposed by UNICEF, and metacognitive strategies on the health of children aged 5 to 8 years during the Corona pandemic.
This study utilized a quasi-experimental intervention design, with a pretest and posttest control group. The participants were 84 children living in Qom, who were randomly divided into 6 groups. There were two age groups, each consisting of three groups: UNICEF, UNICEF Plus, and a control group. The intervention involved 18 sessions of UNICEF-proposed quadruple games. The UNICEF Plus group also engaged in a semi-structured interview to stimulate metacognition.
The results of the Mixed ANOVA and ANCOVA tests indicated that most of the training groups showed a significant improvement in health test results from pretest to posttest. However, the ANCOVA test did not reveal any significant difference between the UNICEF and UNICEF Plus groups in the two age groups; despite the UNICEF Plus group scoring better than the UNICEF group in both age groups.
Overall, it can be concluded that the exercises recommended by UNICEF were effective in promoting children's health. Although the combination of these exercises with metacognitive strategies did not meet expectations, there was a slight improvement in children's health favoring the combined exercises.

Arousal is one of the psychological factors affecting athletes' performance. Without reaching the optimal level of arousal, people's performance will not be optimal. The aim of the current semi experimental study was to investigate the effect of arousal caused by spectators on process and outcome of volleyball service decision making. The population of the present study included volleyball players of Iranian youth volleyball national team. A number of 15 players (Mean age=18.00 ± 1.00 years) participated in this research. The task of current study was performance of volleyball service decision making under arousal conditions caused by spectators. Participants performed 25 decision making situations in baseline and spectators arousal conditions. The visual saccade and fixation data recorded by eye tracker system simultaneously with decision making test performance. Data analyzed with paired-samples t-test. The result indicated that arousal caused by spectators affected the process and outcome of decision making. Although the decision-making speed of the players increased under the circumstances of the arousal, their decision-making accuracy decreased. Given this results, coaches need to provide good training tips in training to improve the decisions made by players. In addition to physical exercise, mental training and decision-making should also be done.

</span> A learning disability is a developmental neurological disorder of biological origin, causing abnormalities at the cognitive level. Psychomotor development relies on the organization of the body program, body balance, and lateral superiority. Motor skills play a significant role in children's learning and development of academic and social skills. Transcranial Direct-Current Stimulation (tDCS) of the brain, a noninvasive technique, is used to treat neurological and psychiatric disorders. The portable tDCS is a wearable brain stimulation technique that delivers a low electric current to the scalp. tDCS neuromodulation technique produces immediate and lasting changes in brain function. This study aimed to investigate the effect of tDCS in the primary motor cortex on the speed of hand preference transfer in children with learning disabilities in overt and covert learning conditions</span>. </span></span></span>

The current research method was quasi-experimental with a pretest-posttest design and a control group. The study population comprised 220 children with learning disabilities referred to the Yazd Education District clinics, in Yazd City, Iran. The study sample included 60 right-handed children with learning disabilities, aged 9-12 years. The subjects were randomly divided into four groups of 15 students. Thirty children were randomly placed in two groups of 15: explicit learning intervention and explicit learning control. Similarly, 30 other children were divided into two groups of 15: implicit learning intervention and implicit learning control. The inclusion criteria were as follows: having an age range of 9-12 years, diagnosis of learning disorder (based on psychiatric records available in children's counseling and rehabilitation centers), no disorder associated with learning disorder, right-handedness (based on the Edinburgh Handedness Inventory), having normal intelligence (according to the Wechsler Intelligence Scale), not taking psychiatric medication, lacking vision and hearing defects and history of seizures, and consent of their parents to participate in this study. The exclusion criteria were as follows: observation of seizures during stimulation sessions and regular non-attendance in tDCS sessions. Before the intervention, the subjects were administered the Serial Reaction Time Task software (Nissen & Bullemer, 1987) and the Edinburgh Handedness Inventory (Oldfield, 1971). The children in the intervention group received 1.5 mA transcranial electrical brain stimulation treatment for 20 minutes in 10 continuous daily sessions. After the intervention, the children were asked to perform the Serial Reaction Time Task. To analyze the obtained data, descriptive statistics indices, including mean and standard deviation, and inferential statistics, including mixed variance analysis, Bonferroni post hoc test, and correlated t test, were performed using SPSS version 18 software. The significance level for all tests was 0.05.</span>

</span> The results for the speed of hand preference transfer of the left hand of children with learning disabilities showed that the main effect of block and learning type were significant (p<0.001). However, other effects were not significant (p>0.05). The results for the speed of hand preference transfer of the right hand of children with learning disabilities showed that the main effects of block and brain stimulation and the interactive effect of block and type of learning were significant (p<0.001). However, other effects were not significant (p>0.05).</span></span></span>

</span> According to the results, the effect of tDCS in the primary motor cortex on the speed of between-hand transfer in children with learning disabilities is effective in overt and covert learning conditions. Therefore, this treatment can be used along with other treatment methods in children with learning disabilities.</span></span></span></span>

In previous studies, the effect of arousal on performance has been investigated. However, whether arousal during learning stages affects bimanual coordination has not been investigated. Therefore, the present research aimed to investigate the effect of arousal levels during different learning stages on the performance of the hand-eye coordination task.

For this purpose, 36 male physical education students aged 20-35 were conveniently selected and based on normal IQ, normal trait anxiety, and right-handedness, were matched into three Low Arousal, Normal Arousal, and High Arousal groups. The study involved pre-test, post-test, retention, and transfer stages. In the pre-test stage, the participants performed 10 trials of the eye-hand coordination task. The training period consisted of 10 sessions and 50 trials per session, in which at the end of each session 10 trials were recorded as performance. The retention and transfer tests were performed 24 hours after the last training session. The data were analyzed using repeated measure analysis of variance, one-way analysis of variance, and Tukey's post hoc tests.

The results of the present study showed that high, normal, and low arousal levels have a significant effect on the duration of the eye-hand coordination task during the cognitive, association, and automatic stages, and also the time of the eye-hand coordination task was improved.

According to the results of the study, it is suggested that educators use these arousal stimulation effects to improve the performance and learning of athletes in pursuit tasks.

Peripheral neuropathy is the most important factor in the incidence of foot and amputation in diabetes. the purpose of this study was to investigate the effect of aerobic exercise in water and land on the irritability of sensory of the hands and soles of the diabetic patients. 24 participants were assigned randomly in three groups Control, aerobics on land, aerobics in water. Aerobic training involved 12-weeks (2 times·week-1). Before and after the training period, the marks on the hand and the foot of the patients were measured and recorded by the neurothesiometer machine. MANKOVA and dependent t-test were used to analyze the data. The results of MANKOVA test for intergroup comparisons in the post-test did not show a significant difference in any of the variables of sensory irritability in the soles of the feet and hands between the groups (P≥0.05).The results of intra-group comparisons using dependent t-test showed that aerobic exercise in water has a significant effect on the sensory irritability scores of the palms and soles of the feet of diabetic patients (P≤0.05).However, this significant effect was seen only in the scores of the soles of the aerobic exercise group on land (P≤0.05);Also, the control group did not show a significant difference in any of the variables from pre-test to post-test (P ≥0.05). the result that aerobic exercise in water is due to the creation of hydrostatic pressure, it can have more impact on the bottom of the palm and foot of the diabetic patients.

Sports Vision training is a set of techniques for developing visual function. the present study aims to investigate the effect of sports vision training on the eye movements of children with ADHD.
In this semi-experimental study, 27 male students (average age=8.55±1.08 years old) with ADHD were randomly selected and they were divided into experimental and control groups after filling out the Conners questionnaire and clinical psychiatric interviews. At first, the horizontal and vertical saccades and Near-Far-Near (NFN) tests were performed as pre-test by means of the HART CHART of the subjects. Afterward, the experimental group performed the sports vision training during 12 sessions (three sessions a week about 30 minutes), but the control group didn’t perform any intervention. In the end, the subjects performed a post-test.
The results of mixed ANOVA showed that the experimental group's horizontal and vertical saccades and NFN improved with sports vision training in all three variables (P≤0.005). Independent t-test showed a significant difference between the two groups in the horizontal and vertical saccades and NFN tests.
Sports vision training significantly improves eye movements in children with ADHD.

Evaluating variability can help to investigate the process underlying motor coordination problems. The current study aimed to measure motor coordination and its variability in children with Developmental Coordination Disorder (DCD). Moreover, the symmetry of motor coordination variability in these children and the relation between motor skills and variability were explored.

After evaluating motor skills in children, aged 7-10 years using Movement Assessment Battery for Children-2 (MABC-2), 15 children with DCD and 20 non-DCD children performed a bilateral coordination task. Using motion capture system, motor coordination and variability were recorded and calculated by computing continuous relative phase and its standard deviation, respectively.

The study with an ethical code of IR.UT.SPORT.REC.1396030 was approved by Ethics Committee of Faculty of Physical Education and Sport Sciences of University of Tehran.

Children with DCD showed significantly higher variability, while there was no significant difference between the groups in performing the coordination task. Moreover, the variability of motor coordination was found asymmetrical in children with DCD. Finally, more variability was shown to be accompanied with lower score in motor skills of the participants.

The current study shows the necessity of employing assessments related to underlying process of movement coordination such as variability, which can help to provide more comprehensive understanding of motor patterns of children with DCD and the strategies that they adopt to execute and produce movement.

The purpose of this study was to examine the effect of motor dependent/independent visual perception training on visual-motor integration and fine motor skills of 7-8 year old children .For this purpose, 107,  1st grade  primary school students in Sabzevar were selected through purposive sampling (with equal economical and cultural status , optimum mental and physical health and full sight with or without wearing glasses) and randomly divided into two experimental (no=32)and a control group (no=43). After attending a pre-test session, one of the experimental groups was trained in movement dependent visual-perception tasks while the other group performed movement independent visual-perception tasks.  Both groups performed their tasks for three sessions, 45-minute per week and for six consecutive weeks. Shapiro-Wilk and Levin test results confirmed the normality and homogenity of data and ANCOVA showed that both training programs significantly improved visual-motor integration and fine motor skills of 7 to 8 years old children. However, Bonferroni test indicated that there were no significant differences between the movement dependent and independent training programs. The data analysis was performed by using SPSS 19.0. The results of this study confirmed the purposed "movement" hypothesis stating that the significant contributor to the development of perception and perceptual-motor components is not the active or passive movements of the individual, but rather it is the attention of the person to the visual stimuli within the environment.

Primary stress can impair the nervous structure including the hippocampus and behavioral functions such as memory; therefore, paying attention to neutralizing the destructive effects of stress on the body has been one of the debatable topics among researchers. Considering the role of physical activity in reducing stress in previous studies, this study aimed to investigate the effect of four weeks of swimming training on learning and spatial memory in neonatal rats separated from their mother.

In this study, 40 male albino Wistar rats were randomly divided into four groups (separation from mother, separation from mother and swimming training, swimming training, and control). The method of separating the infants from the mothers was used to make stressful conditions. Rats from separation groups were separated from mothers 6 h per day starting from the day after birth for one month. For physical activity, swimming training was performed for four weeks (five sessions per week) incrementally to measure stress and blood glucose level in mice, and the Morris Water Maze test was used to assess the learning and spatial memory.

The results of the analysis of variance test showed that the blood glucose in the group of rats that were separated from their mothers was significantly higher, compared to the control group (P=0.045), indicating that stress was successfully induced in these rats. Moreover, the results of the multivariate analysis of the variance test showed that although stress had no significant impact on spatial learning, the results of the exploration test showed a significant decrease in the percentage of entering the target quadrant (P=0.05) and the time spent in the target quadrant in the group separated from mother (P=0.029), compared to the control group. Therefore, spatial memory was degraded due to stress in the group of rats that were separated from their mother, compared to the other groups. However, swimming training in the group of rats that was separated from the mother could neutralize the destructive effects of stress on spatial memory and the percentage of entering the target quadrant (P=0.02) as well as the time spent in the target quadrant (P=0.05).

The results showed that although stress did not have a negative impact on spatial learning, it had a destructive impact on memory. On the other hand, swimming training as a treatment method could largely neutralize the negative effects of stress and improve memory.

The aim of this study was the effect of internal and external attention on anticipatory motor plannig. in people with MS. Thirty patients with mean age of 34 (age mean= 34±2/43 , EDDS=4-6) with criteria for participation in the study. to prevent the effects of sequencing on task assignment to a subgroup The three focus groups were internal, external, and non-instructional. In this study, the Bar- transfer task was used for anticipatory motor planning. Interventions focused on the focus of attention on the thumb and on the external attention to the Bar. Analysis of variance with repeated measures was used to investigate the effect of different types of focus onanticipatory motor planning. The results showed that external focus in the Bimanual task led to an increase in comfortable end state and non-instructional effort resulted in better internal focus as well as Stroop test score, executive functions, and weksler test with most project conditions and assignments. There was a significant relationship between most conditions and assignments. Also, Pearson correlation coefficient test results showed that there is a significant negative relationship between Stroop test score and executive functions with predictive planning in two-handed and two-handed assignments in all attentional focus conditions, and also between the numbers of the number-calling test and the Predictive projection in the two-handed and two-handed assignments was significantly correlated across all attentional conditions.

Behavioral studies in team sports are typically constrained by dynamic factors, such as positioning of defenders for interception. Handball player have to coordinate their steps when running to throw a ball on goal from a different positions. In this study were analyzed the movement patterns during locomotors pointing, throwing velocity and accuracy of 12 succesful elite handball players under defensive constraints (defender- absent, defender-far, defender-near, or defender pairing). It was captured data from the locomotors patterns of the attacking participant by speed camera with 120Hz, throwing speed by sports radar gun and throwing accuracy by camera. ANOVA with repeated measures and Bonferroni post hoc test and Friedman test was used to analyze effects of these constraints on gait and throwing parameters. In addition to Pearson and Spearman correlation coefficient test was used to analyze speed-accuracy trade off (P<0.05). The results revealed significant differences in overall mean movement velocity, first and second step mean velocity, first and second step mean length. For the mean foot/gate area distance variability was shown pattern of ascending/descending variability in all defense conditions. Since regulation of offensive players was continuous and based on perception of current and required behaviors, results supported from perception-action coupling and prospective control models of locomotors pointing. Also it is suggested that the technical aspects of the running and throwing in handball can affect by nested tasks constraints.

Despite decades of efforts by the international community against terrorism, especially after the terrorist attacks of 9/11-2001, two decades later, it has not succeeded in suppressing it. Terrorism, on the other hand, is increasingly undermining international peace and security. What the international community has become skeptical about and challenged in the present age through the commission of terrorist crimes is the lack of a proper and universal definition in identifying all aspects and manifestations of this phenomenon. The definition has made the distinction between legitimate and liberating struggles and the use of terrorism and the possibility of abusing the right to self-defense. However, international conventions and even counterterrorism zones, despite providing numerous instances of terrorist offenses, have not yet come up with a single and comprehensive definition of terrorism; While we can refer to war and its definition in the four Geneva Conventions. In addition, the lack of a definition of terrorism can be traced to the lack of a clear structure and framework for achieving consensus between governments and international organizations, according to which a common global definition and approval of terrorism can substantially facilitate the counter-terrorism process.

Celebrity culture is one of the basic concepts for understanding actions in the context of social media. Social media has a special ability to create celebrity culture. Among these, Instagram is of interest to researchers due to its image-oriented nature and the creation of an interactive space for users and celebrities. The purpose of this study, on the one hand, is to examine the celebrity culture and its consequences, and on the other hand, to examine the extent to which users or audiences follow the personal pages of celebrities. In this research, survey method and questionnaire technique are used to collect data. In the theoretical section, "Celebrity Culture Approach", "Celebrification and Celebritization Approach", "Celebrity Ecology Approach", "Celebrity Private and Public Space Approach" and "Psychological Approach to Advocacy and Celebrity" are discussed. Findings show that about 20% of Instagram users follow news and celebrity pages. The pages of domestic celebrity actors, singers and athletes are followed more than any other celebrity group. As a result, about a third of users follow the personal pages of actors and celebrity singers, and about a quarter of users follow the personal pages of athletes.‌ Para-Social Interaction, identification and worship are the three main indicators of tendency to celebrities. Our study shows that approximately 47% of active users in this subject pay attention to celebrities; so that, in addition to the interest in Para-Social Interaction with them, they intellectually follow the values and attitudes of celebrities and behaviorally imitate their celebrity lifestyle.