نشریه مطالعات کاربردی علوم زیستی در ورزش
پیاپی 28 (زمستان 1402)

Resistance training (RT) plays a major role in developing muscle mass and strength. This study aimed to compare the effect of eight weeks of modified German volume resistance training (MGVRT), high-intensity resistance training (HIRT), and non-linear resistance training (NLRT) on the serum levels of myostatin (Mstn), follistatin (FLS), nuclear factor kappa B (N F-κB), and muscle mass and strength in male athletes.

Forty young men bodybuilders were randomly assigned into equal groups, including MGVRT, HIRT, NLRT, and control. Training protocols were performed for eight weeks (three times a week). Selected biochemical variables, muscle mass, and strength were measured before and 48 hours after the last training session. For statistical analyses the analysis of covariance, repeated-measures analysis of variance, Kruskal-Wallis, and Mann-Whitney U test‏s were and significance level was set as p≤0.05.

The Mstn and FLS protein levels significantly decreased and increased, respectively in all three experimental groups compared with the control group. Moreover, the NF-κB level was significantly lower in the MGVRT and HIRT groups than NLRT and control groups. Furthermore, the arm and thigh circumference and muscular strength in the chest press and squat movements significantly increased in all three experimental groups as compared with the control group where the increase in arm circumference in the MGVRT group was significantly higher than in the HIRT and NLRT groups and as the same the muscular strength in the HIRT group was significantly higher than in the MGVRT and NLRT groups.

All three RT protocols lead to improve biochemical, anthropometric, and functional indices in male athletes, but the MGVRT and HIRT protocols led to more increase in muscular hypertrophy and maximum strength, respectively. However, further studies are needed on the relationship between RT protocols with muscle mass and strength, and the biochemical parameters associated with them.

Evidence shows that certain conditions during pregnancy will have lasting effects on the fetus. The aim of this study was to investigate the effect of a period of voluntary physical activity on corticosterone and anxiety levels in mice during and after pregnancy.  

In this experimental study, 40 female NMRI mice aged with an approximate age of 80 to 90 days and a weight of 25 to 30 grams were divided into four groups of 10 including the control-pregnancy, experimental-pregnancy, control-postpartum and experimental-postpartum groups. After two weeks of adaptation to the environment and seeing the vaginal plaque, two rotating wheels were placed inside the cage of each pregnant mice to apply voluntary physical activity for four weeks. The dark-light box test was used to measure the anxiety of mice. Finally, the animals of the pregnancy groups, on the 18th day of pregnancy and the samples of the postpartum groups, on the 7th day after delivery; were given deep anesthesia and to measure corticosterone, blood was taken directly from the heart tissue. For statistical analysis, the independent sample t-test was used at a significance level of p<0.05.

The serum corticosterone levels decreased significantly in the experimental groups during pregnancy (p=0.002) and during the postpartum periods (p=0.006). However, the anxiety level of the mice was significantly reduced only in the experimental postpartum group (p=0.007).

The use of voluntary physical activities during pregnancy in mice is probably important as an effective therapeutic strategy in reducing cortisol and psychological disorders including anxiety.

Multiple sclerosis (MS) is a chronic disease of the central nervous system that affects the brain and spinal cord and cause disturbances in the conduction of nerve and electrical currents. The aim of this study was to investigate the effect of eight weeks of combined training on the expression of neuregulin-1 gene, balance and body composition in patients with MS.

Materials and Methods:

 Thirty women with MS mean age 47.7±4.79 year and weight 69.70±5.5 kg living in Mashhad city were randomly divided into two experimental (15 people) and control (15 people) groups. The experimental group performed combined exercises including resistance exercises with an intensity of 65 to 85% of a one maximum repetition and aerobic exercises with 60 to 70% of maximum heart rate for eight weeks, three days a week, and 45 minutes in each session while the control group did not participate in any sports program during this period. Blood samples were taken from the brachial vein before and 48 hours after exercise in a fasting state. Neuroglin-1 gene expression ​​were determined using Real Time PCR method. Balance index was measured by BDI and TUG tests, and body composition also was measured using a body composition analyzer. Data were analyzed using independent t-test and paired t-test at the significant level of p≤0.05.

Combined training significantly increased neuregulin-1 gene expression (p=0.001), static balance (p=0.001), dynamic balance (p=0.001), lean body mass (p=0.001) and significantly decreased fat body mass (p=0.001) in MS people.

Based on the findings of the present research, combined exercises can improve the conditions of MS patients by increasing the influencing factors in the illness.

Since saffron has potential properties such as antioxidant and anti-inflammatory effects, it can play a role in modulating inflammatory factors caused by intense sports activities. Therefore, the aim of this research was to investigate the short-term effect of saffron extract consumption on the serum levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) and cortisol in young men after an intense exercise session.

The present research was semi-experimental. Twenty-four male students were randomly divided into two groups (saffron and placebo). Blood sampling was done before and immediately after 30 minutes of vigorous activity with an intensity of 85% of the maximum heart rate stored on the treadmill. After completing the pre-test, the saffron group consumed 400 mg of saffron extract for 15 days, and the placebo group consumed the same amount of starch flour. Then, like the pre-test, two blood samples were taken again before and immediately after intense activity. IL-6 and TNF-α serum levels were determined by ELISA method and cortisol by radioimmunoassay method. Extraction of the results was done using covariance analysis test at a significance level of p≤0.05.

After the implementation of the intense aerobic protocol, the concentration of cortisol (p₌0.01) and TNF-α (p₌0.02) in the saffron supplement group was significantly lower than the placebo group; However, there was no statistically significant difference in serum IL-6 levels between the two groups (p<0.49).

short-term consumption of saffron before intense activities can moderate the release of some inflammatory indicators and cortisol, and is desirable for athletes involved in intense activities.

Telomeres play an important role during aging process. Chronic psychological stress and high cortisol levels could damage the telomere. The effect and mechanism of physical-mental exercise on changing the level of telomerase enzyme as a telomere protector is unknown. Therefore, the aim of this study was to evaluate the effect of hatha yoga exercises on telomerase, cortisol and stress in middle-aged women.

During this quasi-experimental trial, 24 middle-aged women with high perceived stress scale (PSS>27) were purposefully and accessibly selected and randomly divided into two groups including exercise (n=12) and control (n=12). The exercise group participated in hatha yoga exercises for eight weeks, two sessions per week for 60-90 minutes each session. Forty-eight hours before and after the training protocol, blood cortisol and telomerase levels were measured by ELISA and stress levels were measured using the Cohen perceived stress scale. Data were analyzed using analysis of covariance and linear regression tests at a significance level of p<0.05.

Serum levels of telomerase enzyme significantly increased and cortisol and stress were significantly decreased (p= 0.001) in the exercise group compared to the control group. A significant negative correlation also was observed between baseline cortisol and telomerase levels in both exercise (p=0.02) and control (p=0.001) groups, as well as a significant negative correlation at changes due to hatha yoga exercise was observed in the exercise group (p=0.003); Moreover, 56% of telomerase changes based on cortisol changes were predictable.

Hatha yoga physical-mental exercise can be a good method to reduce the aging process caused by psychological stress in middle-aged women who have high levels of stress, by increasing serum telomerase levels via the cortisol reduction mechanism.

It is well-documented that physical fatigue from sports activities can negatively affect the immune system’s structure and function. Nutritional measures are suggested to delay fatigue and prevent the decline of immune system performance. The is study aimed to investigate the impact of an eight-week soccer preparation program and beta vulgaris supplement consumption on the content of OPA1 and MFN1 proteins in peripheral blood mononuclear immune cells of young male soccer players.

The study involved thirty male soccer players with an average age of 20.1±1.72 y. who had regularly participated in training and competitions in Shiraz in the two years prior to the study. The participants were divided into two groups, with one group consuming beta vulgaris supplementation (n=15) and the other group receiving a placebo (n=15).  The training program consisted of eight weeks of soccer preparation training, with three sessions per week. Before each training session, the players in the beta vulgaris group consumed 50 g of beta vulgaris supplement, which contained 6.13 mmol of nitrate dissolved in half a liter of water. The content of OPA1 and MFN1 proteins of mononuclear immune cells was measured before and after the intervention using the ELISA method. The data were analyzed using repeated measures of ANOVA test at p<0.05.

A study found that there was a significant increase in the MFN1 protein in both the exercise-supplement group (p=0.001) and the exercise-placebo group (p=0.009). Additionally, there was a significant increase in the OPA1 protein only in the exercise-supplement group (p=0.001), but not in the exercise-placebo group (p=0.72).

The study concluded that soccer training and beta vulgaris supplement can prevent disruption of the mitochondrial biogenesis process by increasing the content of MFN1 and OPA1 proteins.

Among the many variables that affect muscle growth are myokines and myostatin. This study looked at how resistance-aerobic training affected the expression of genes related to fibronectin type III domain-containing protein 5 (FNDC5), myostatin and hypertrophy or hyperplasia in the immature rats’ gastrocnemius muscle.

A total of ten male Wistar rats, aged two weeks were randomly divided into two control (five rats) and training (five rats) groups.  The resistance training program consisted of three sessions each week for six weeks, during which time the participants would carry a weight and climb a one-meter ladder 26 times. For six weeks, on alternate days, aerobic exercise consisted of jogging on a treadmill at an intensity between 25 and 50% of a rat’s maximum speed. All of the rats were dissected and their skeletal muscles isolated 48 hours after the previous training session and after fasting for 8 hours. FNDC5 and myostatin expression were measured using Real-Time PCR. Using light microscopy, hypertrophy and hyperplasia were quantified. Prism software was used to analyze the data using an independent t-test at the p≤0.05 level.

Following six weeks of training, the training group had higher gene expression of FNDC5 (p=0.04) and hypertrophy (p=0.004) than the control group, but decreased gene expression of myostatin (p=0.01) in comparison. Nonetheless, there was no statistically significant difference between the two groups gastrocnemius muscle hyperplasia (p=0.22).

It appears that resistance-aerobic exercise accompanied by increased expression of FNDC5 genes and decreased myostatin gene expression increased fast twitch fiber hypertrophy. This approach shows that muscle tissue in animal samples before puberty is trainable, independent of natural growth.