نشریه مطالعات کاربردی علوم زیستی در ورزش
پیاپی 19 (پاییز 1400)

Body composition is closely related to health and exercise performence. Therefore, the purpose of the present study was to compare the substrate metabolism and mechanical efficiency during running on a treadmill in lean, obese and normal-weight girls.

For this purpose, 9 lean girls (body fat 19.17 ± 3.56 percent), 9 obese girls (body fat 42.29 ± 4.42 percent) and 9 normal-weight girls (body fat 27.23 ± 3.58 percent) volunteered in the research project. The exercise plan was to run on a treadmill with an intensity of 75% of maximum heart rate for 30 minutes. The fat and carbohydrates oxidation, energy expenditure and mechanical efficiency of the subjects were measured with a gas analyzer system duing 30 minutes in the baseline and 30 minutes during activity. Then, the collected data were analyzed using multivariate variance analysis and LSD tests at the level of p < 0.05.

During the activity phase, the fat and carbohydrate oxidation and mechanical efficiency of the obese subjects were significantly higher as compare to lean and normal individuals (p=0.001, p=0.001, p=0.04 respectively). Moreover, absolute energy expenditure during the exercise at the obese subjects was significantly higher than lean subjects (p=0.02).

According to the results of the present study obese girls, compared to lean and normal weight ones, indicated higher substrate metabolism and net mechanical efficiency.

Soccer requires high levels of physical fitness, therefore coaches and athletes tend to do comprehensive training exercises such as concurrent training. The aim of this study was to investigate the effect of 4 weeks of concurrent resistance-endurance training on strength, power, and maximum oxygen consumption in young male soccer players.

Thirty young soccer players aged 18 to 20 years with an average height of 177±8 cm and a weight of 70±3.4 kg were divided into two groups of concurrent high-intensity training and low-intensity training. Both groups performed their training protocol, 3 sessions per week during 4 weeks. Before and after 4 weeks, maximal oxygen consumption were measured using the Yo-Yo Recovery Stage 1 test, as well as upper and lower limb strength and leg power also were measured by maximal muscle strength test and sargent vertical jump test respectively. Paired and independent t-tests were used to evaluate intra-group and inter-group changes, respectively, where the significant level set as p < 0.05.

Concurrent resistance-aerobic training improved muscle power and strength in both groups (p=0.05), but only concurrent resistance-aerobic training with high intensity indicated significant effect in maximizing oxygen consumption (p=0.03).

Overall, the results showed that high-intensity resistance-aerobic training is more effective in improving some of the physical fitness factors in young men soccer players.

Apoptosis in post-mitotic tissue such as the heart is fatal due to the unable to proliferate and loss of cardiomyocytes is irreplaceable. However, exercise training could be effective in reducing apoptosis. The aim of this study was to investigate the role of 3 months of regular aerobic training on some factors of mitochondrial apoptosis pathway in cardiac tissue of male Wistar rats.

The research was applied study that conducted in the form of an experimental project with a control group. Thirty one male Wistar rats with an average weight of 173.80 ± 9.21 grams were divided into three homogeneous groups including three-months control (n=10), six-months control (n=10) and aerobic training group (n=11).The aerobic training group participated in aerobic training with 75 to 80 percent of maximal oxygen consumption for 3 months. After the implementation of the training protocol, the surgical procedures and cardiac tissue extraction were performed and gene expression of Bax and Bcl-2 of cardiac tissue was assessed by RT-PCR. Results extracted by one-way of variance analysis and Bonferroni post hoc test at a significance level of p<0.05.

The results showed the significant increase in Bcl-2 gene expression during aerobic training compared to the six-month control group (p=0.001). However, the expression of Bax gene in the aerobic training group did not show any significant changes compared to the control group (p=0.21).

Regular aerobic exercise can play a significant role for controlling mitochondrial apoptosis of cardiac tissue.

Exercising without proper recovery is likely to leave sports-related injuries or cause pain to the athletes. Therefore, the aim of present study was conducted to investigate the effect of six weeks of dedicated football training and various recovery methods on the speed, vertical jump and muscle damage of football players.

Thirty six young and elite football players of Birjand city were selected purposefully and randomly divided into 4 groups of passive recovery, active recovery, floating in cold water and massage. Subjects first took a 20-meter back and forth running session to the point of exhaustion and then participated in a 20-minute recovery procedure. After that, they practiced football for 6 weeks, and then they did a session of instrument making, and at the end they participated in one of the 20-minute recovery methods. The lactate dehydrogenase (LDH) and creatine kinase (CK) indices were measured by Elisa, velocity by the double-run Bangsbo velocity test, and anaerobic power by the Sargent jump test. The results were extracted using analysis of variance with repeated measures, dependent t-test, and tuky test at the p<0.05 level.

Inactive recovery and massage methods following 6 weeks of special football training reduced LDH enzyme (p=0.01 & p=0.04 respectively) and massage recovery method reduced CK enzyme (p=0.001) in participants. On the other hand, cold water recovery improved athletes’ speed (p=0.01), but cold water recovery and massage methods improved vertical jump (p=0.01).

The immersion in cold water and active recovery between training sessions accelerates the recovery of physical functions (speed and explosive power) and reduces the indicators of muscle damage (CK & LDH) of football players.

Fetuin-A is a liver-secreted cytokine that has been linked to a number of diseases correlated to obesity and its related metabolic diseases such as insulin resistance and type II diabetes. The purpose of this study was to investigate effects of high intensity interval training (HIIT) on serum levels of Fetuin-A, insulin, fasting glucose, and insulin resistance in young obese women.

Twenty obese women randomly divided into two groups including experimental (mean age 32.5±4.14 years, and body mass index 33.18±6.12 Kg/m2) and control (mean age 35.45±2.33 years, and body mass index 31.58±1.65 Kg/m2) groups. Subjects in experimental group participated in the eight weeks of HIIT including one minute of running interval up to 90-95 percent of maximal heart rate and 1-3 minutes of rest interval up to 50-60 percent of maximal heart rate, 20 minutes per session, and three sessions per week. Blood factors and body composition indices were assessed before and after training protocol. Statistical analysis was done by the covariance and paired t-test at the significant level of p < 0.05.

Based on the covariance analysis, the changes in serum levels of Fetuin-A (p=0.04), insulin (p=0.03), weight (p=0.001), body mass index (p=0.005), body fat percent (p=0.0001), and waist circumference (p=0.002) were significantly decreased after HIIT compared to control group.

It seems that decreased level of Fetuin-A following HIIT do not play a role in improving insulin resistance in young sedentary obese women.

Controlling obesity can be considered as important part of public health; and physical exercise is recommended as an essential intervention for modulate obesity. The aim of this study was to investigate the effect of 8 weeks of continuous running on serum concentrations of Meteorine like protein and Interlukin-6 (IL-6) in male rats with metabolic syndrome.

The present was an experimental study. 24 Wistar male rats, with age 6 weeks old and weight 150-180 gr randomly divided into two groups including standard diet (SD, n=8) and high fat diet (HFD, n=16). They were then placed on a pre-exercise diet for 12 weeks. After this period, 8 rats from each groups of SD and HFD were selected to determine syndrome metabolic state through lipid profile and Insulin serum content measurements. Moreover, 16 rats from HDF group were divided randomly into two groups including metabolic syndrome control (Ctr+MetS, n=8) and continuous running (CT, n=8). The aerobic continuous running protocol, included 65-75% of maximum speed performed from week 1 to 8 At the end of intervention, serum levels of Meteorine like protein and IL-6 were assessed through specific rats ZellBio kits. One way ANOVA and Tukey post hoc tests were used to determine mean differences between groups. Data were analyzed using SPSS version 20 and the significance level was set as p≤0.05.

Eight weeks of continuous running didn’t indicate any significant effect (insignificant increase) on serum meteorine level (p=0.09) but showed a significant increase on interleukin 6 in metabolic syndrome group (p=0.001).

It seems that 8 weeks of continuous running have a little impact on inflammation induced obesity through modulating of meteorine-like protein and IL-6.

Improper diet and reduced physical activity are associated with cardiovascular diseases. Due to the fact that the role of high intensity interval training (HIIT) and caloric restriction on oxidative stress in the heart tissue is not well understood, the aim of this study was to investigate the effect of 8 weeks of HIIT with and without caloric restriction on glutathione peroxidase (GPx) activity, malondialdehyde (MDA) and carbonyl protein (PC) in the heart tissue of high-fat diet (HFD) rats.

In this experimental study, 24 obese male rats were divided into 4 groups including high-fat diet, high-fat diet+caloric restriction, high-fat diet+ caloric restriction+HIIT, and high-fat diet+HIIT. Besides, 6 rats were assigned in the healthy control group. The HIIT program was performed for 8 weeks, 3 sessions per week with  high intensity, and the rats on the diet received high-fat diets during the same period. The GPx and MDA indices were measured by Elisa and PC by spectrophotometry methods; then results were extracted by the one-way analysis of variance and Tukey tests at the significant level of p < 0.05.

The PC levels in the high-fat diet+caloric restriction (p=0.001), high-fat diet+HIIT (p=0.001) and high-fat diet+caloric restriction+HIIT (p=0.01) groups were significantly lower than the high-fat diet group. This variable was also significantly lower in the high-fat diet+HIIT group than the high-fat diet+caloric restriction (p=0.005), and high-fat diet+caloric restriction+HIIT (p=0.001) groups. On the other hand, MDA in the high-fat diet+HIIT group was significantly lower than the high-fat diet (p=0.03), and high-fat diet+caloric restriction+HIIT (p=0.009) groups. GPx values in the high-fat diet+caloric restriction+HIIT group were significantly higher than the high-fat diet (p=0.001) group.

HIIT improves oxidative stress indices more than caloric restriction, while combined HIIT and caloric restriction was only effective in improving GPx in the heart tissue of high-fat diet rats.

Resistin is an adipose tissue derived adipokines that play important role in obesity and insulin resistance. The aim of present study was to investigate the effects of 8 weeks resistance training with two different intensities on serum levels of resistin and insulin resistance in obese elderly women.

Thirty obese elderly women (mean age of 64.5±3.64 years and body mass index of 31.8±1.02 kg/m2) randomly divided into 3 groups including control, low intensity resistance training (LIRT), and high intensity resistance training (HIRT) groups and each group consisted of 10 subjects. The HIRT (80% of one repetition maximum) and LIRT (30% of one repetition maximum) performed for 8 weeks, 3 sessions per week while  control group did not participate in any training program. Blood sampling collected in both pre and post-test stages and then resistin levels and insulin resistance were measured. The data analyzed by analysis of covariance and Tukey post hoc tests at the significant level of p < 0.05.

Rresistin levels between different groups were not significant (p=0.29); however, decreased insulin resistnace and body fat percent were observed in the LIRT and HIRT groups compared to control group (p=0.001).

Resistance training with low and high intensity independent of changes at the resistin levels is accompanied by the favorable changes in the metabolic condition in obese elderly women.