درخت حوزه‌های تخصصی

Purpose: For most trainers, the relationship between training volume and intensity as key components is a very important and effective issue. Therefore, the aim of the present study was to investigate the relationship between two key components of exhausting running at Heart Rate Deflection Point (HRDP) in girls. Methods: A number of 40 girls of physical education of Mohaghegh Ardabili University were selected as subjects with an age range of 19 to 23 years. Then, they ran individually in four separate sessions with an intensity of 70, 80, 90 and 100% of heart rate breaking point with a minimum interval of 72 hours. Using non-linear regression, the relationship between exercise volume and intensity was analyzed. Results: The findings showed that the inverse relationship between the volume (as a dependent variable) and the intensity (as an independent variable) of exhausting running at the HRDP of young girls' follows the non-linear 2nd degree function. Conclusion: According to the results of this study, it can be said that the inverse relationship between the volume and the intensity of running is non-linear. The noteworthy point is that in this estimation, the training volume was fitted based on the intensity, the relevant equation, which has a practical aspect for sports science trainers and researchers. Heart rate, as an important physiological index available to all coaches, can easily estimate the running time of young girls using the fitted equation.

Background and purpose: Caffeine is a widely used and available physiological stimulant that is effective in sports performance. The purpose of this study was to investigate the effect of caffeine consumption and exercise on fatigue and cardiovascular responses in active men.Materials and methods: The statistical population of this research was made up of all male students of physical education in the age range of 19 to 27 years with at least three activity sessions per week. 15 of them were selected as subjects and they performed the exercise protocol in two stages (the first stage by eating placebo and the second stage by eating coffee). Subjects consumed 5 mg/kg of coffee in the first session under placebo conditions, and in the second session, subjects consumed 5 mg/kg of coffee one hour before the test. Blood samples were collected before taking placebo or caffeine and after the test. Findings: The results of the correlated t-test showed that the consumption of caffeine supplements significantly increased the time to reach fatigue and the index of oxygen consumption after exercise. In general, it can be said that active men can use 6 mg/kg of caffeine supplement one hour before sports activity to improve the time to reach fatigue.

Purpose: This study aimed to investigate the relationship between gut microbiome composition, athletic performance, and post-exercise recovery in endurance athletes following probiotic supplementation.  Method: In this randomized, double-blind, placebo-controlled study, 40 male endurance runners (age: 28.3 ± 5.2 years) were randomly assigned to either a probiotic (n=20) or placebo (n=20) group for 8 weeks. The probiotic group received a daily supplement containing a blend of Lactobacillus acidophilus, Bifidobacterium lactis, and Lactobacillus plantarum (20 billion CFU total). Fecal samples were collected before and after the intervention and analyzed using 16S rRNA gene sequencing. Athletic performance was assessed through VO2max testing and time to exhaustion. Recovery was evaluated by measuring delayed onset muscle soreness (DOMS) and creatine kinase (CK) levels. Results: The probiotic group showed a significant increase in gut microbial diversity (Shannon index: p<0.01) and relative abundance of beneficial bacteria such as Bifidobacterium and Lactobacillus (p<0.001). Significant improvements were observed in VO2max (4.7%, p<0.05) and time to exhaustion (7.2%, p<0.01) in the probiotic group compared to placebo. The probiotic group also demonstrated reduced DOMS (23%, p<0.05) and lower peak CK levels (18%, p<0.01) relative to the placebo group. Multiple regression analysis revealed that changes in Akkermansia muciniphila and Bifidobacterium abundances were significant predictors of performance improvement (R² = 0.68, p<0.001). Conclusion: This study provides evidence that gut microbiome modulation through probiotic supplementation can enhance athletic performance and accelerate post-exercise recovery in endurance runners. These findings suggest that targeted manipulation of the gut microbiome may be a novel strategy for improving sports performance and recovery.

Purpose: Osteoporosis is a multifactorial disease of the skeletal system and the main cause of fractures and death in elderly people, especially postmenopausal women. The purpose of this study was to investigate the effect of eight weeks of resistance training on some serum and metabolic markers of bone mass in postmenopausal women. Methods: 24 inactive postmenopausal women with an age range of 46-58 years participated in this study. Subjects were assigned to resistance training and control groups. Before and after the training period, weight, body mass index, alkaline phosphatase, calcium, serum phosphorus and bone density of lumbar vertebrae were measured (by Dexa method). The training protocol consisted of upper and lower body resistance training in 3 sets of 8 to 12 repetitions for 8 weeks and 3 sessions per week. Data were analyzed using SPSS software version 26 and independent t and paired t statistical tests. Results: The results of this research showed that the experimental group had a significant increase in the amount of alkaline phosphatase (p=0.041), serum calcium (p=0.035) and bone density of the lumbar vertebrae (p=0.11) and a significant decrease in weight compared to the control group. (p=0.035, and body mass index p=0.021). The results also showed no significant change in the amount of serum phosphorus (p=0.071). Conclusion: According to the findings of the present study, in order to maintain or prevent the decrease in bone density of postmenopausal women, resistance exercises can be recommended.

Purpose: Obesity is a complex disease that causes oxidative stress by disrupting fat metabolism. The aim of this study was to investigate the effect of ten weeks of swimming exercises with nigella sativa (Black Seed) supplementation on the plasma lipid profile of inactive obese women. Method: In this study, 40 inactive obese women with a body mass index (BMI) higher than 26, and an average age (29.06 ± 7.94 years), were voluntarily selected and randomly divided into four groups of 10 people. The control group, the training group, the training group - nigella sativa supplement and the nigella sativa group were divided. The control group had a normal diet and no training; the nigella sativa supplement group consumed 2 nigella sativa capsules of 1000 mg daily for 10 weeks; The swimming training group performed swimming exercises for 10 weeks and three sessions a week with an intensity of 60% of the maximum heart rate and the duration of each session was 75 minutes; the nigella sativa -training group also performed both the training and supplement protocols. At the end of the period, blood indicators of (low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG) and total cholesterol. Total (TC)) and anthropometric variables were measured. Covariance analysis and paired t-test at a significance level of 0.05 were used for data analysis. Results: Investigations showed that there is no significant difference between the groups in the values of HDL-C, LDL-C, TG and TC (P>0.05). However, in the intra-group comparison, hockey results have a significant difference in HDL-C, LDL-C, TG and TC in the exercise and exercise +supplement and nigella sativa groups (P>0.05). Conclusion: It seems that taking two weeks of swimming exercises along with nigella sativa supplement improves some of the fat profile indicators and can probably be effective in improving the complications caused by obesity.