درخت حوزه‌های تخصصی

Background: Gene polymorphisms are related to athletic performance. Angiotensin converting enzyme gene polymorphism is essential in identifying talent and guiding adolescents to appropriate sports. Aim : The aim was to investigate the relationship between the angiotensin gene and endurance performance of novice adolescent wrestlers in Ardabil. Materials and Methods: Subjects were 15 Amateur adolescent wrestlers in Ardabil (age: 13.07±1.53 years, height: 164.60±10.68 cm, weight: 60.14±6.32 kg, BMI: 22.22±4.98 kg/m 2 ) with three-year wrestling. Chest and thigh muscle endurance, abdominal fat percentage and cardiovascular endurance, chest press, and squat muscle endurance were measured. ACE polymorphism was determined using tetra-ARMs polymerase chain reaction (PCR) and compared direct DNA sequencing in salivary samples. Chi-square and ANOVA were used to compare frequencies and their relationship with performance indicators. Results: ACE DD genotype frequency was higher in novice adolescent wrestlers, and there was a significant difference between ACE polymorphism frequency ( P =0.008). There was a significant difference between ACE genotype distribution with endurance performance of pectoral and triceps ( P =0.004) muscles, body composition ( P =0.0001), and Vo 2 max ( P =0.0001). There was a significant difference between body composition and Vo 2 max of Amateur adolescent wrestlers with ACE DD ( P =0.0001), ACE II ( P =0.0001), and between body composition and Vo 2 max with ACE II ( P =0.0001), ACE DD ( P =0.0001), and ACE ID ( P =0.0001). In body composition, ACE II was significantly higher compared to ACE DD ( P =0.0001) and compared to ACE ID ( P =0.0001). Also, in Vo 2 max, ACE II was significantly higher compared to ACE DD ( P =0.0001) and compared to ACE ID ( P =0.0001). Conclusion: Findings showed the superiority of ACE DD polymorphism and its relationship with the endurance performance of novice adolescent wrestlers in Ardabil. ACE DD polymorphism is probably essential in wrestler success. Other research with more subjects and other genes is important.

Background: Fatigue as one of the physiological factors can affect the physical performance of athletes. This issue is more important in young athletes and can expose them to injury. Aim: The purpose of this research was to investigate the effect of functional fatigue on the performance and landing mechanics of adolescence taekwondo athletes. Materials and Methods: This was a semi-experimental study. Participants were 20 male teenage taekwondo players. Pre-fatigue measurements included side-jump tests, figure-8 hop tests, and single-leg triple jump tests, as well as a lower limb biomechanics assessment using a landing error scoring system. After the functional fatigue protocol was applied, all the pre-fatigue variables were evaluated again. In order to examine the intra-group changes of the research variables in the pre and post-test stages, the paired t-test at a significance level of P≤0.05 was used. Results: The paired-t test results revealed that following fatigue induction, performance in the side-jump and figure-8 hop tests significantly deteriorated (P<0.05). Additionally, performance in the single-leg triple hop test declined (P<0.05). Moreover, landing error significantly increased (P<0.05). Conclusion: The finding of this study indicated that after applying fatigue, the subjects' performance decreased and the biomechanical error of the lower limbs increased. Fatigue can significantly impact adolescent taekwondo athletes' performance and biomechanics. So, taekwondo coaches should implement effective strategies to mitigate fatigue, enhance athletes' conditioning, and optimize their performance in training and competitions.

Purpose: The aim of this study was compares the effects of 10 weeks High Intensity Interval training (HIIT) and moderate intensity aerobic training (MIAT) on serum levels of homocysteine and some cardiovascular risk factors in overweight inactive men. Methods: In this semi-experimental study, nineteen overweight men voluntarily participated in this study and were randomly divided to 2 Groups: High Intensity Interval training (HIIT) and moderate intensity aerobic training (MIAT). Subjects performed training programs for 10 weeks, 3 sessions per week. The levels of homocysteine and lipid profile were measured before and after 10 weeks of training programs. For statistical data analysis, independent and paired t tests were used and considered significant at a p≤0.05.   Results: The results of this study showed that both High Intensity Interval training and moderate intensity aerobic training caused a significant reduction of homocysteine levels (P≤0.05). After 10 weeks of high -intensity periodic exercise, cholesterol levels (p = 0.001), LDL (p = 0.002) decreased significantly and HDL levels were significantly increased (p = 0.001), In MIAT training group, only a significant reduction in cholesterol was found (P=0.006). Conclusion: According to the results of this study, it seems that both High Intensity Interval training and moderate intensity aerobic training have favorable effects in reducing body weight and some cardiovascular risk factors.