درخت حوزه‌های تخصصی

Purpose: The aim of this study was to investigate the effect of high-intensity interval training on serum levels of irisin, follistatin, and metabolic status of overweight and obese women. Methods: The current research was a semi-experimental type with a pre and post-test design. 30 women with an average age of 22.9±2.11 years, weight 82.45±6.1 kg, BMI above 28 kg/m2) voluntarily participated and they were randomly divided into two groups of 15 people including HIIT (4 bouts of 60 seconds of running at an intensity of 80-90% HRmax with a 4-minute rest in the first four weeks) and control (did not have a regular exercise program). Blood samples were taken 24 hours before the start of the training period and 48 hours after the end of the last session, to measure irisin, Follistatin, and metabolic status, by ELISA method. Then, an independent t-test was used to examine changes between groups, and a correlated t-test was used for intragroup comparison. Data analysis was done by SPSS version 25 software at a significance level of 0.05. Results: After 8 weeks of intervention, the HIIT group showed that HIIT exercises led to a significant increase in irisin(p=0.25) and follistatin(p=0.12), triglyceride (p=0.30), and total cholesterol levels. (p=0.41), LDL (p=0.14), VLDL (p=0.17), weight (p=0.31), fat percentage (p =0.21)) and BMI (p=0.251); And there was a significant increase in maximum oxygen consumption (p=0.11). However, no significant change was observed in the amount of HDL (p=0.55). 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: 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.

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: The purpose of the present research was to investigate the effect of eight weeks of progressive resistance exercise and a subsequent detraining period on the indicators of muscle fiber shortening (FS%) and the relative wall thickness (RWT) of the left ventricle in low-mobility women. Method: This semi-experimental study was conducted in a field-laboratory setting. A total of 32 sedentary women, who met the criteria for participation and were able to engage in the exercise protocol, were randomly assigned to two groups: 1) Resistance training group (16 participants), and 2) Control group (16 participants). Anthropometric characteristics, body composition, and structural indices such as left ventricular muscle fiber shortening percentage (FS%) and relative wall thickness (RWT) were measured using an echocardiography device at three intervals: before the start of training, at the end of 8 weeks of training, and after a 4-week detraining period. The training protocol was implemented over 12 weeks, consisting of 8 weeks of training with three sessions per week, followed by 4 weeks of detraining. Data were analyzed using independent t-tests and repeated measures analysis of variance (ANOVA) at a significance level of p < 0.05, using SPSS version 21. Results: The results showed a significant difference in FS% between pre-test and post-test measurements for both the experimental and control groups (p < 0.05). Additionally, a significant decrease in FS% was observed in the training group during the detraining period (p < 0.05). Similarly, a significant change in RWT was found between pre-test and post-test measurements in both groups (p < 0.05), and significant changes in RWT were also observed during the detraining period in the training group (p < 0.05). Conclusion: Based on these findings, it can be concluded that 8 weeks of resistance training led to beneficial changes in the structure and function of the heart in sedentary women. However, the 4-week detraining period resulted in negative effects on these adaptations. Therefore, it is recommended that individuals engage in regular and structured resistance training to maintain these positive adaptations.