فصلنامه پژوهش های فیزیولوژی و مدیریت در ورزش
سال پنجم شماره 2 (تابستان 1392)

It is necessary and important to using effective systems to select, attract, maintain, evaluate and develop national team coaches which will be realized through a proper performance evaluation system. 360 degree feedback is one of the recent evaluation systems which provides more realistic and accurate evaluation of performance through gathering different beneficiarie's viewpoints. Therefore, the aim of this study was to evaluate the performance of volleyball national team coaches by 360 degree feedback. Statistical population included all male and female athletes, coaches and supervisors of Iran volleyball national teams in four age levels. The statistical sample equaled the population. To collect data, “performance evaluation criteria for national team coaches" questionnaire was used which was designed by Shafiei (2009). In this questionnaire, 40 criteria in 4 total subscales including technical skills, managerial skills, social skills and personality characters were designed. Results showed no significant difference between the evaluation scores of athletes,peer coaches, supervisors and self-evaluation of volleyball national team coaches in managerial, technical and social skills and personality characters. But, when these skills were fully investigated, there was a significant difference among groups in 19 skills out of 40 skills. Finally, necessary feedbacks were provided to optimize coache's behaviors through recognizing differences in their viewpoints, weaknesses and strengths.

Melatonin has an important role in the regulation of cardiovascular system, and the reduction of melatonin is associated with an increase in vasoconstriction and finally in blood pressure and heart rate. According to the positive effect of melatonin on cardiovascular indexes, the main aim of this study was to investigate the effect of melatonin consumption on some heart contractility parameters during exercise in active men. For this purpose, 12 students of Imam Reza University(mean age 22±3, weight 72.7±9.80, BMI 23.2±2.63) were selected to participate in this study. The participants were tested once in the control group (without melatonin consumption) and once in the experimental group (with melatonin consumption). Bruce test was conducted in two different days, with 72 hours of interval at 1 p.m. and the results were recorded. After 72 hours, 10 milligrams of melatonin supplement were consumed 30 minutes before the exercise. Heart contractility indexes were measured using the cardio-screen system. The data were analyzed with SPSS 16, descriptive statistics and paired t test at p<0.05. The results of the study revealed that heart rate, systolic time ratio reduced significantly after melatonin consumption (p˂0.05). Stroke volume, blood acceleration index and blood velocity index increased significantly after melatonin consumption (p˂0.05). However, left ventricular ejection time did not change significantly (p˂0.05).Hence, it was concluded that probably 10 mg of melatonin consumption improved the pressure on cardiovascular system of males during the exercise.

The aim of the current study was to rank the indicators involved in selecting the coaches of football national teams in Iran. The research was descriptive and application, a survey and field study. The population of the study involved football experts and coaches working in football premier leagues, league 1, league 2, at different age groups. The sample of 160 subjects was selected through non-random convenience sampling. Kolmogorov-Smirnov and Friedman tests were applied. Two researcher-made questionnaires were used to collect data and their face and content validity were verified by 20 university professors, teachers and elite football experts; and the questionnaires’ reliability was assessed according to Cronbach’s alpha (α=0.79). The results of Friedman test showed a significant difference among the indicators involved in selecting football national team coaches in each four characteristics including personality, technical, emotional-human, and management skills (P<0.01). According to research findings as well as the ranking of indicators, the presented framework can be suggested as a determined principle to select Iran football national team coaches at different age groups.

The aim of this study was to examine the relationship of thoracic kyphosis with cardiorespiratory endurance and the endurance of core stability muscles in the trunk of university students aged between 18 and 20. Statistical sample included 194 female and 154 male new students in academic year of 1390-91 in Tehran University of Medical Sciences who were randomly selected. A flexible ruler was used to measure thoracic kyphosis angle. 20 m shuttle run was used to evaluate cardiorespiratory endurance and a series of functional tests derived from deep stability exercises were used to evaluate the endurance of core stability muscles. The results showed a significant negative relationship (P < 0.05) between increased thoracic kyphosis and cardiorespiratory endurance and the endurance of core stability muscles of the trunk (p˂0.05). Proper planning seems necessary due to the high incidence of increased thoracic kyphosis and low level of cardiorespiratory endurance in those students who enter the universities from schools.

The aim of this study was to examine the relationship between job competencies and socioeconomic status with self-efficacy of physical educators. Statistic sample included all physical education teachers in guidance and high schools in North Khorasan province (N=301) who equaled the statistical population. A researcher-made questionnaire of personal characteristics, job competencies and socioeconomic status (SES) with internal reliability of 0.81 and the Jeffrey J. Martin’s self-efficacy questionnaire (2003) with the internal reliability of 0.83 were used to collect data. Kolmogorov-Smirnov test, Pearson, Spearman correlation coefficients and chi² test were used to analyze data at p≤0.05. Results showed no significant relationship between personal characteristics, socioeconomic status and sport experiences (a part of job competencies) with self-efficacy of teachers while there was a positive significant relationship between educational courses (r=-0.12) and field of study (r=-0.007) with self-efficacy. Also, there was a negative significant relationship between educational level and self-efficacy (r=-0.122). Thus, it seems necessary to improve job competencies and the proportion of job responsibilities to educational level in order to maintain and increase self-efficacy in physical educators.

Hypoxia inhibits the endostatin production. Also, blood circulation endostatin increases with physical activity in proportion to peak oxygen consumption. Thus, physical activity can be considered as a beneficial effect against atherosclerosis and hypoxia as angiogenesis stimulators. The aim of this study was to evaluate the effect of a single bout of high-intensity intermittent exercise in hypoxic conditions on serum endostatin in non-athlete men. 9 available healthy sedentary men participated voluntarily in this study. Serum endostatin levels at different times (before, immediately after and two hours after high-intensity exercise) were collected from the subject's brachial vein and were determined by ELISA method. The results of the present study showed a significant reduction (0.024) in serum endostatin levels during a single bout of high-intensity intermittent exercise under hypoxic conditions. Serum endostatin levels were 8.72±1.25, 6.92±1.14 and 8.30±1.28 ng/ml before, immediately after and 2 hours after the exercise. The results of the present study showed that hypoxic conditions along with high-intensity intermittent exercise reduced serum endostatin levels of blood circulation.

This study aimed to determinate the relative contribution of managerial factors in brand loyalty in Iran football premier league clubs. The study was an applied survey. The statistical population consisted of the fans of Iran football premier league. The sample (n=842) was estimated by statistical formula. In order to collect the data, two questionnaires were used: the Managerial Factors Questionnaire by Chen (2007); the reliability of this questionnaire was estimated by Cronbach’s alpha as (0.86) and the researcher-made Brand Loyalty Questionnaire; the reliability was estimated by Cronbach's alpha as (0.72). The validities of both questionnaires were established for this study. The data were analyzed by SPSS 15, Pearson correlation coefficient, liner regression and multivariate regression. The results showed a correlation between five managerial factors of clubs and fan's brand loyalty (P=0.01). Also, the results of multivariate regression test showed that three factors of attractiveness, affiliation and media could be reliable predictors of fan's brand loyalty. These factors generally explained more than 44% of the variations of the dependent variable.

Rationale for dietary-sport supplements to improve physical and sport performance is based on this assumption that they may have an effect beyond diets and even exercise. The aim of this study was to investigate the effect of consuming arginine supplement (at rest) and along with resistance exercise on the response of growth hormone (GH) in non-athlete men. For this purpose, after completing the health and physical activity questionnaire, 16 healthy male university students (mean+SD age: 24.81±0.91 yr, body mass index: 24.20±3.37 kg/m2 and body fat percentage: 14.28±5.33) were selected and divided into two groups of arginine and placebo. Both groups participated in two resistance exercise sessions similarly in a cross-over design. Arginine subjects consumed 7 gr of arginine 30 min. before the resistance exercise. The intra-group test of Friedman and intergroup test of Wilcoxon were used to analyze data at p<0.05. The results showed that consuming arginine supplement alone (at test) and also the combination of arginine and resistance exercise (arginine group) had no significant effect on GH secretion when compared to placebo group. On the other hand, the resistance exercise had a significant effect on the GH secretion compared to the combination of arginine and resistance exercise. It can be concluded that the combination of arginine and resistance exercise had no superiority on GH response over the resistance exercise.