فصلنامه علوم زیستی ورزشی
پیاپی 48 (بهار 1400)

This study aimed to compare high intensity interval training and continuous endurance training on the gene expression of mir-1 and IGF-1 in cardiomyocytes of diabetic rats. After induction of diabetes, 21 male Wistar rats were randomly divided into three groups (each group 7 subjects): control, continuous endurance training, high intensity interval training). The training program included 5 days a week for 8 weeks. Each endurance session consisted of 30 minutes of running with the intensity of 60% VO2max. Each interval session consisted of 4 intervals, each interval 3 minutes, with the intensity of 90% VO2max and 1 minute of recovery with the intensity of 30% VO2max between each two intervals. Gene expression of IGF-1 and mir-1 of left ventricle tissue was assessed by qRT PCR. The results showed that both types of training significantly reduced the gene expression of mir-1 compared to the control group, but this decline was severer in the high intensity interval group than the endurance group (P≥0.05). Also, the gene expression of IGF-1 significantly increased in both training groups compared to the control group but this increase was severer in high intensity interval group than the endurance group (P≥0.05). It seems that high intensity interval training can be an effective intervention to reduce the complications of diabetic cardiomyopathy by repression of mir-1.

ABCG8 is a cellular membrane transport protein that induces cholesterol efflux. The aim of this study was to investigate the effects of a period of cardiac rehabilitation on ABCG8 gene expression. 20 middle-aged men (50 to 60 years old) that experienced CABG, were assigned to two groups (control (n=10) and experimental (n=10)). Aerobic exercises were performed for 8 weeks (3 sessions per week) with the intensity of 11 to 13 (moderate intensity on the basis of Borg scale) under the control of a physician. Blood samples were collected after 12 to 14 hours of fasting 48 hours before and 48 hours after the exercises. RTPCR method was used to examine the gene expression of ABCG8 in both groups. Analysis of data using independent t test showed that ABCG8 gene expression in PBMN cells increased and lipid profile improved in experimental group (P≤0.05). According to research findings, ABCG8 gene expression after cardiac rehabilitation in PBMN cells is one of the mechanisms related to reverse cholesterol transport that can affect the prevention of recurrent myocardial infarction after CABG.

The aim of this study was to investigate the effect of 12 weeks of high intensity interval training (HIIT) on gene expression of DRP1, MFN2 and OPA1 in cardiac muscle of type 2 diabetic male Wistar rats. Therefore, 20 rats (age: 10 weeks old and mean weight: 220±20 g) were divided randomly into 2 groups: diabetic control (n=10) and diabetic HIIT (n=10). The training protocol was performed for 12 weeks, 5 days a week with specific duration and intensity. 48 hours after the last training session, ventricular cardiac samples were obtained for further genetic experiments. Independent t test was used for data analysis (P≤0.05). The results showed no significant difference in MFN2 gene expression between diabetic control and diabetic HIIT groups (P=0.337). But 12 weeks of training significantly increased gene expression of DRP1 (P=0.001) and OPA1 (P=0.001) proteins in diabetic rats. It can be generally stated that HIIT may positively regulate gene expression of mitochondrial dynamics in diabetes.

Obesity contributes to disrupt balance between coagulation (increasing) and fibrinolysis (decreasing) factors and is effective in inducing thrombosis. Physical activities play a role in controlling the damages caused by obesity. Therefore, the aim of this study was to investigate the effect of 8 weeks of aerobic and resistance training on PAI-1, fibrinogen, PT, PTT, t-PA, plasminogen and D-dimer. 30 sedentary women (age: 25-30 years, body mass index: 30 Kg/m2) voluntarily participated in this study and were randomly divided into three groups: aerobic training, resistance training and control. Aerobic training was performed 3 sessions a week, 30-45 minutes each session with an intensity of 60-85% of maximum heart rate. Resistance training was performed based on 10RM, following the principle of overload for 8 weeks. Data were analyzed by ANOVA and dependent t test (P<0.5). Aerobic training significantly increased tPA compared to control and resistance training groups (P=0.001). Both resistance and aerobic training significantly increased prothrombin time (PT), PAI-1, plasminogen and D-dimer (P=0.001) compared to the control group. Aerobic training significantly increased (P=0.001) and resistance training significantly decreased (P=0.003) fibrinogen compared to the control group. The partial thromboplastin time (PTT) increased in the resistance training group (P=0.03) and decreased in aerobic training group (P=0.001) compared to the control group. Aerobic training has a better effect on important fibrinolysis factors including t-PA, while resistance training has a better control on some important coagulation variables including fibrinogen

Obesity is one of the most important public health challenges of the present century, which increases the plasma levels of inflammatory cytokines and decreases anti-inflammatory and anti-atherogenic agents. High intensity interval training may be able to stop or reverse these destructive effects. Therefore, the aim of this study was to investigate the effect of 8 weeks of interval training on inflammatory factors in overweight adolescent boys. In a quasi-experimental research project, from overweight adolescent boys (13-18 years old, mean height 154.33 cm, mean body mass index 27.05 kg/m2), 30 subjects were voluntarily assigned to 3 groups (10 subjects each group): short-term interval training (nine 30-second bouts, 100 to 110% of maximum speed with 150 seconds of rest), long-term (four 150-second bouts, 90 to 95% of maximum speed with 240 seconds of rest) and control. 48 hours before the beginning and the end of the training protocol, weight, height, body mass index and fat percentage were measured by a body composition apparatus and blood samples were collected to determine the interleukin-6, interleukin-10 and C-reactive protein indices. The results showed that 8 weeks of high intensity interval training increased interleukin-10 and decreased C-reactive protein. But it had no significant effect on interleukin-6. It was also found that there were no differences between short-term and long-term HIIT in influencing the desired indicators. Based on these findings, it can be said that overweight or obese adolescents may be able to use HIIT to boost their anti-inflammatory system by increasing interleukin-6 and decreasing C-reactive protein. But more studies are needed to determine the effect of this training on interleukin-6.

Resistance training with blood flow restriction (BFR) as a training strategy preventing joint and tissue injuries, increases anabolic hormones, hypertrophy and muscle strength. Therefore, the aim of this study was to investigate the effect of 12 sessions of rock climbing with BFR on testosterone, cortisol and their ratio in elite rock climbers. In this quasi-experimental study with a pretest-posttest design, 20 male rock climbers (weight: 64.55±4.69 kg, fat percentage: 15.30±8.50 and age: 26±2.6 years) were selected purposively and were randomly divided into two training groups (10 men each) with BFR and without BFR. The training protocol was 4 weeks and 3 sessions of rock climbing per week. Blood pressure was about 40 to 100 mm Hg. Fasting blood samples were collected 24 hours before and after training to determine testosterone and cortisol levels. Also, the strength of the dominant hand grip and climbing speed were measured. Data were analyzed using paired and independent t tests at P<0.05. Results showed that the testosterone (P=0.02), the ratio of testosterone to cortisol (P=0.03), hand grip strength (P=0.006) and climbing speed (P=0.03) increased significantly after rock climbing training compared with the period before the training. Also, cortisol did not change significantly in both groups after the training compared with the period before the training (P=0.54, P=0.85). It seems that rock climbing training with BFR increases anabolic hormones and it can be used to improve the performance of rock climbers.

The aim of this study was to investigate the relationship between serum levels of salusins and lipid profile, insulin resistance, cardio-respiratory fitness, body composition and body fat percentage after a period of selected interval training with different intensities in overweight/obese women. In this study, 40 sedentary women were divided into 3 homogeneous groups purposively: control (BMI=30.2±2.8 kg/m2, n=14), moderate-intensity interval training: 75-80% HRmax (BMI=31.2±3.3 kg/m2, n=13), and high-intensity interval training: 90-95% HRmax (BMI=30.19±3.4 kg/m2, n=13). The subjects of experimental groups participated in the interval training (pedaling) with different intensities for 8 weeks. Blood samples were collected 48 hours before the first training session and 48 hours after the last training session. The research variables were measured under similar conditions. Pearson correlation coefficient test was used to statistically analyze the data (P<0.05). The findings revealed significant positive relationships between salusin β levels and total cholesterol, salusin α and HDL and salusin α and cardio-respiratory fitness; there was a significant reverse relationship between salusin α and body fat percentage. It seems that interval training with different intensities can influence the improvement of cardio fitness and general health of obese individuals. Since there is a considerable relationship between the intensity of interval training and the improvement of cardio-respiratory fitness, insulin resistance and lipid profile, high-intensity interval training is recommended to improve well-being of this group of people.

Decreasing muscle mass is one of the detraining characteristics that associated with attenuated in muscle strength and muscle performance, and resulting in disability in performing of daily tasks. The purpose of the present study was to investigate the effect of decreased physical activity in the form of chronic constriction injury (CCI) on the Tweak and Fn14 proteins after resistance, endurance and combined exercises. 32 rats were randomly divided into four groups: 1- Control group-CCI (Sham+CCI), 2- Mixed training group-CCI (Mix+CCI), 3- Endurance training group-CCI (TE+CCI), and 4- Resistance training group-CCI (LA+CCI). Mix+CCI, TE+CCI and CCI+SNL groups participated in training program for six weeks. After performing 6 weeks training, chronic constriction injury was implemented for four weeks. Western blotting technique was used to measure proteins. The results extracted by ANOVA and showed that Tweak and Fn14 proteins increased by CCI. The level of Tweak and Fn14 proteins in CCI+La and CCI+Mix groups and also CCI-TE group was significantly lower than Sham+CCI group (P <0.05). One the other hands, the level of Fn14 protein in CCI-LA compared with CCI-TE and CCI-MIX was not significant (P >0.05). According to the findings of the present study, it seems that mice that had resistance training in their training program experienced less atrophy than the group that did only endurance training.