درخت حوزه‌های تخصصی

Purpose: The purpose of this study was to investigate the effect of creativity on performance with the mediating role of knowledge sharing in sports federations. Method: This field study was a descriptive-correlative research and a practical one. The research population consisted of all presidents, vice presidents, general secretaries, committee managers and experts in 51 sport federations (N=780), and 267 subjects were studied through stratified random sampling approach that was consistent to recommended sample by Krejcie & Morgan table. The research tools were adopted from the existing literature to collect the data. The reliability of the research tools were confirmed according to Cronbach’s alpha. Face, content, and construct validity were used to evaluate the validity of the research tools. To test the research hypotheses, structural equation modeling was conducted by applying Smart PLS. Results: The findings demonstrated that "Creativity" had a positive and significant effect on "Performance", as well as "Knowledge sharing". Moreover, "Knowledge sharing "had a positive and significant effect on "Performance". The results also showed that "Knowledge sharing" mediate the relationship between "Creativity", and "Performance "in sport federations. Conclusions: The findings of this study, with emphasis on the role of creativity and knowledge sharing in improving the performance, can be regarded as a platform for enhancing the performance of sports federations. Creativity and knowledge sharing can play a significant role in empowering the human capital that ultimately result in performance development.

Introduction: Musculoskeletal Disorders (MDs) largely contribute to occupational diseases in the workplace. Prevention from these disorders requires their evaluation in different occupations. This study aimed to compare the MDs of the neck between the teachers of Physical Education (PE) and those of the other majors in the high schools of Tehran City, Iran. Methods: The study sample included 180 teachers of mathematics, PE, and the religion and lifestyle in the high schools of Tehran (with the Mean±SD age of 42.11±6.65 years, and the Mean±SD weight of 72.28±12.98 kg). The participants were selected from 19 districts of the Tehran Departments of Education using multistage cluster sampling. The standard Nordic questionnaire was administered to investigate MDs among the teachers. The obtained data were analyzed with the Chi-square test to compare the MDs of the neck between the three groups of teachers. Results: A significant relationship was observed between the neck problems of the female (P=0.016) and male (P=0.017) PE teachers and the other teachers. Moreover, the neck problems were associated with the teaching experience (P=0.024) and teaching major (P=0.004). Conclusion: Based on the results, it seems that regular exercise can reduce the developing risk of MDs in the neck. Thus, this study recommends the performance of regular exercise and the correction of job-related postures to all teachers.

The phenomena of fatigue of voluntary muscular effort is intricate and multidimensional in the field of sports sciences. The causes and effects of exercise-induced fatigue have been extensively studied, but the central nervous system's (CNS) involvement in this process is still unclear. In order to understand CNS fatigue after physical activity, the current review will examine changes in neurotransmitter function during exercise. Using primary sources such scientific journals and websites, a consensus and critical evaluation were carried out in order to accomplish this goal. For a number of neurotransmitters, including dopamine and serotonin (5-HT; 5-hydroxytryptamine), hypotheses have been established. The most well-known one is a rise in serotonin levels throughout the brain. Nutritional interventions intended to reduce brain serotonin synthesis during extended exercise enhance endurance performance, and there is strong evidence that increases and decreases in brain serotonin activity during prolonged exercise, respectively, accelerate and delay fatigue. There are several physiologically connected causes of fatigue. It is important to better understand how CNS effects affect fatigue in order to achieve maximum muscle performance in both daily life and athletics.