فهرست مطالب علی اکبر جابری مقدم

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.

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.

The purpose of this study was to investigate The effect of Success Confirmation Feedback, Error Correction Feedback, and both on the Soccer Kick Accuracy under Open and Closed Conditions.

For these purpose 45 students 10 to 14 years participated in the study. after the pre-test participant, randomly divided into 3 groups: Success Confirmation Feedback, Error Correction Feedback, and both. In acquisition phase, all groups performed 30 trials and after each trial, they received relevant feedback. the post-test was performed after the last session of acquisition, and retention and transfer tests also were performed after 24 hours.

the results of repeated measures showed that under Open and Closed Conditions the Error Correction Feedback group ,from pre-test to post-test, retention and transfer phase was a significant improvement in their performance (p

Introduction and goal: focus of attention and competition is an integral part of the sport and the factors affecting the performance and motor skills. The aim of this study was to examine the effect of the interaction of attentional focus types and competitive environmen on performance and learning over arm throwing in high school student.

60 male students with a mean age (16.95 ± 0/819) and unfamiliar with the research they were studying in Tabriz voluntarily participated in this study and were divided into four groups of 15 persons (external focus on non-competitive environment, internal focus on non-competitive environment, external focus on competitive environment, external focus on competitive environment). Then in the acquisition level practiced six blocks of ten attempts over arm throwing the earth tennis ball in conditions with each group. Retention and transfer tests were performed after 24 hours from the acquisition.

the results of variance analysis with repeated measures showed that the main effect of block groups and blocks, as well as the interaction between these two variables is significant. One-way analysis of variance and bonferroni test shows significant differences in all phases of the scores and in both competitive and non-competitive external focus group is better than internal focus group. The results also show that all groups in acquisition and retention tests compared to pre-test their progress (P≤0/05). Therefore, it is suggested that coaches and sports teachers in competitive environments also use external attention instructions to learn sport skills.