درخت حوزه‌های تخصصی

Purpose: The activity of plasma liver enzymes is intensified under the influence of sports activities, which is affected by the duration, intensity, type and method of training. The purpose of this study was to investigate the effect of a special endurance training session on the activity of serum alkaline phosphatase and aspartate aminotransferase liver enzymes in inactive young men. Methods: In this semi-experimental study, 16 young inactive men were purposefully selected and examined in two groups (experimental and control). The experimental group performed Bruce's protocol after preliminary warm-up. Blood samples were collected before the test, immediately after the test, 24 hours and 48 hours after the test from both groups at the same time, and the amount of serum ALP (Alkaline Phosphatase) and AST (Aspartate Transaminase) enzymes were measured using an Auto analyzer. Statistical analysis of the data, independent T-test was used to compare the results of two groups and Bonferroni's post hoc test was used to determine the difference between different stages of sampling with a minimum significance level (P≥0.05). Results: The results of the independent T-test in the comparison between the groups showed that there is a significant difference between the two groups in the amount of ALP enzyme in the time intervals immediately after the activity (P≥0.020), but in the time intervals of 24 (P≥0.177) and 48 hours (P≥0.136), there is no significant difference between the two groups after the activity. The results of the independent T test did not show any significant changes in the amount of AST enzyme in any of the time intervals in the comparison between groups. Conclusion: Fatigue-inducing sports activity leads to an increase in the amount of enzymes, ALP, this increase can be a sign of damage to liver cells or heart muscle. Considering the role of recovery in liver damage, it seems that by considering enough rest time, it is possible to help improve the adaptation process while preventing the occurrence of muscle and liver damage

The aim of this study was to develop a model for examining the mediating role of job characteristics in the relationship between structural empowerment and professional commitment of referees in female's Futsal Premier League. To collect the required data, we distributed the research questionnaires among 75 Futsal Premier League referees invited to the pre-season qualifying class in 2020, and finally we received 63 valid questionnaires. We conducted structural equation modeling, confirmatory factor analysis and path analysis for data analysis by using PLS Smart software. The findings demonstrated that structural empowerment can predict professional commitment, but the relationship between the two variables was not significant. The relationship of structural empowerment with job characteristics and professional commitment was not significant. The mediating role of job characteristics in the relationship between the two variables was not significant. The components of information sharing in structural empowerment, attachment to professional commitment and diversity of skills in job characteristics had the highest averages. Given that the lack of significance of the relationship among structural empowerment, professional commitment and job characteristics, is questionable and it should be assessed in great details.

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.

Background : Work-related musculoskeletal disorder is the most important occupational disease that threatens the health of employees. Aim: The aim of this study was to investigate the relationship between workers' posture and musculoskeletal disorders. Materials and Methods: Eighty-two male and female workers working in a home appliance factory participated in this cross-sectional study. Musculoskeletal disorders were investigated using Nordic questionnaires. Posture evaluation was performed to measure the angles of forward head, rounded shoulders, and thoracic kyphosis using photogrammetry. Craniovertebral, shoulder, and thoracic kyphosis angles were photographed during the work and then measured using ImageJ software. Data analysis was done using SPSS 26 and Spearman's correlation test at a significance level of 0.05. Results : A significant relationship between the craniovertebral angle and musculoskeletal disorders in the last twelve months was observed in the cervical region ( P <0.001). Also, a significant relationship was observed between the kyphosis angle and musculoskeletal disorders in the last twelve months in the upper back and lower back ( P <0.001). Conclusion : The results showed that the workers’ posture during work is correlated with the prevalence of musculoskeletal disorders. Therefore, it is suggested to pay attention to ergonomic principles during work to maintain and improve the physical health of workers.

Purpose: Haematological, hormonal, biochemical and physical performance parameters were altered after long-term soccer training in professional soccer players. These alterations can be influenced by different contextual factors such as playing surface, training load, duration of training and competition. The purpose of this study was to investigate the changes in the haematological, inflammatory, antioxidant and physical performance of beach soccer players during the competitive season of the beach soccer. Method: The study examined 15 elite beach soccer players in Iranian beach soccer primer league (age 24.64 ± 4.01 y, weight 75.08 ± 8.15 kg, height 181.00 ± 5.17 cm, body mass index 22.76 ± 2.36) from the pre-season, mid-season and end-season. Measurements of haematological, inflammatory, antioxidants indices and aerobic / anaerobic power were repeated in the pre-season, mid-season and end-season. Repeated-measures analysis of variance was used to examine indicators change during league season. Results: Significant decrease in SOD (p = 0.001), TAC (p = 0.043) and anaerobic power (p ≤ 0.048) and significant increase in GPx (p = 0.001), ALT (p = 0.022) was observed from pre-season to the end of the season. LDH levels showed a significant increase in the mid-season compared to the pre-season (p = 0.042) and a significant decrease at the end of the season compared to the mid-season(p = 0.014). However, no significant changes were observed in other indices during the competition season(p ≥ 0.05). Conclusions: It is suggested that some physical and physiological fatigue markers ar increase during mid-season. Therefore, beach soccer players may be  monitored  continuously during the competition season in order to be able to provide the best training, nutrition and recovery systems for performance optimization. Coaches may use the interplay between biomarker alterations and physical performance changes to better manage workload and monitor fatigue during beach soccer training and competition.

Transference of professional sports clubs to private sector involves the necessary conditions for private sector activity. Therefore, the aim of this study was to determine the prerequisites for the transference of professional football clubs in Iran with emphasis on economic requirements. Statistical population included all CEOs and members of board of directors from professional football clubs, chairmen of committees and officials of provincial football boards, sports management and economics professors as well as football reporters. The research tool was a valid and reliable researcher-developed questionnaire. Factor analysis and Friedman ranking test were employed to analyze the research data. According to the results, the prerequisites for privatization were categorized in seven factors including cultural, executive, programming, motivational, legal, economic, and structural. Moreover, economic requirements (4.20) were the most important category, followed by executive (4.14), structural (4.04), motivational (4.02), legal (3.99), programming (3.97), and cultural requirements (3.62), respectively. Among the economic requirements, the transparency of financial information from country's football clubs, presence of strong sponsors and the creation of supportive funds for financial guarantee of private sector are in the first to third ranks, respectively. According to the findings the most important priority is to solve the financial problems and revenue generation of the clubs.

Background: Hyper kyphosis is a common postural issue that affects many women, often leading to negative body image. Aim: The purpose of this research was to investigate the impact of an 8-week corrective exercise program on the body image of women with hyper kyphosis. Materials and Methods: The research method used in this study was quasi-experimental. The study population consisted of female students aged 18 to 26 years with hyper kyphosis at Shahid Rajaee University. Participants were randomly assigned to either the experimental group (n=20) or the control group (n=20). Hyper kyphosis was measured using a flexible ruler, while body image was assessed using the Body-esteem Scale for Adolescents and Adults. The questionnaire had a reliability coefficient of 0.83 as measured by Cronbach's alpha. After 8 weeks of corrective exercise, both the experimental and control groups completed the questionnaire again. The control group did not receive any training during this time. The data were analyzed using the mixed ANOVA method with SPSS-26 software at a significance level of 95%. Results: The results of the mixed ANOVA analysis showed that the main effect of the training group and the interaction between the group and test stages were significant in the post-test stage for the dependent variable of total body image (F=6.82, P =0.013), appearance (F=6.72, P =0.014), attitude (F=8.81, P =0.005), and kyphosis angle (F=18.91, P =0.000). However, there was no significant effect of training on weight satisfaction. Conclusion: The results of this study indicate that eight weeks of corrective exercise significantly reduced the hyper kyphosis angle ( P =0.01), resulting in an improvement in the subjects' posture and a decrease in deformity. This improvement in appearance led to an increase in satisfaction with their appearance, as demonstrated by improvements in their body image.