فصلنامه علوم زیستی ورزشی
پیاپی 22 (پاییز 1393)

Resistance exercise is associated with increased oxidative stress. However، it is not completely obvious how resistance training intensity can affect the rest levels of oxidative stress indexes. Therefore، the aim of the present research was to study the effect of moderate resistance (MR) and high resistance (HR) training on oxidative stress. 20 males (age: 20. 6±0. 7 yr، height: 1. 74±0. 06 m، weight: 71. 1±4 kg) voluntarily participated in the research and were randomly assigned to one of the HR and MR groups. Blood samples were collected before and after the training program and activities of creatine kinase (CK)، malondialdehyde (MDA) and total antioxidant capacity (TAC) were measured. The training program was performed for eight weeks، three sessions per week. HR and MR subjects performed the training with 85-90% and 65-70% of one repetition maximum (1RM) respectively. The results showed no significant difference in CK، TAC and MDA in the interaction of group and time of two resistance training protocols (P≥0. 05). However، both MR and HR groups decreased MDA significantly after the training (P≤0. 05). But there were no significant changes in CK and TAC compared with the pretest (P≥0. 05). It can be concluded that both MR and HR training can decrease MDA and oxidative stress. It seems that this decrease is separate from the intensity of the training.

Increasing the intensity of physical activity is associated with reduced risk of cardiovascular diseases and this may be the reason why the blood lipoprotein profiles improve. So the aim of this study was to investigate the effect of six weeks of a high intensity interval training (HIIT) on lipid profile of sedentary young men. For this purpose، 18 sedentary young men voluntarily participated in this study and were randomly divided into training group (n=9، age=24. 33±1. 41 yr، height=176. 22±4. 91 cm، weight=72. 27±6. 59 kg) and control group (n=9، age=23. 27±2. 01 yr، height=180. 22±6. 88 cm، weight=76. 27±7. 23 kg). The training group performed the high intensity interval training for 6 weeks and 3 sessions per week. Blood samples were collected before and after six weeks of high intensity interval training in the fasting state. Data were analyzed by paired t test and independent t test. The results showed a significant decrease in body fat percentage of the training group (P=0. 019). Although serum concentrations of triglycerides، low-density lipoprotein، total cholesterol and the ratio of total cholesterol to high-density lipoprotein decreased and high-density lipoprotein levels increased، these changes were not statistically significant (P>0. 05). These findings indicated that six weeks of HIIT led to an insignificant relative improvement in lipid profile in sedentary young men and a significant decrease in fat percentage of the training group as well. According to these results، implementation of HIIT may be an efficient factor to prevent and improve the cardiovascular disease risk factors in sedentary young men with regard to the time effect.

The aim of the present study was to examine the effect of 8 weeks of resistance training and HMB supplementation on serum myostatin levels of non-athlete men. In this quasi-experimental study، 20 non-athlete men voluntarily participated in the study and were divided into experimental group (n=10، mean age 28. 75±1. 39 yr، height 179. 83±4. 30 cm، weight 81±5. 27 kg and BF% 28. 65±6. 40) and control group (n=10، mean age 28±2. 14 yr، height 180. 25±3. 71 cm، weight 84. 23±3. 58 kg and BF% 29. 21±5. 97). Both groups performed the 8-week resistance training protocol (5 sets، 3 sessions per week، 50-80% 1RM intensity). Experimental group ingested 3 gr of HMB daily while placebo was used in the control group. Fasting blood samples were obtained prior to the training and 48 hours after the last session of the training protocol. The results of independent t test revealed that HMB supplementation had no significant effect on serum myostatin level. The findings of this study leads to the conclusion that HMB supplementation has no significant effect on myostatin inhibition.

Omentin-1 is a novel adipokine that is predominantly secreted by visceral adipose tissue. Circulating levels of omentin-1 is inversely related to obesity. There is limited information about the effect of exercise training on serum omentin-1 concentration. The aim of this study was to investigate the effect of four weeks of progressive resistance training on serum omentin-1 levels. 16 male Wister rats (mean weight 288±19 g) were randomly divided into control (n=8) and training (n=8) groups. The resistance training consisted of climbing a ladder (8 repetitions/day، 3 days/week) carrying a load suspended from the tail with weights equivalent to 50، 75، 90، and 100% of their previous maximal carrying capacity and 30 g increment for each subsequent climb. After four weeks of resistance training، serum concentration of omentin-1، glucose and lipid profile were measured. Four weeks of progressive resistance training increased strength (maximal carrying capacity) in rats. Also، no significant difference was observed in serum concentration of omentin-1، glucose and lipid profile between the groups (P>0. 05). Changes of body weights in the resistance training rats were significantly lower than the control group (P=0. 049). The results of this study indicated that serum levels of omentin-1 and lipid profile remained unchanged in rats despite of increased strength and prevention of weight gain induced by resistance exercise. Further studies are needed to elucidate the effects of exercise training and body composition on circulating levels of omentin-1.

Heart produces and secretes a hormone called atrial natriuretic peptide. The aim of this research was to investigate the effect of eight weeks of resistance and sprint training on ANP of non-athlete men. 36 non-athlete healthy men were randomly divided into three groups (12 subjects each group): resistance (mean age ± SD: 33. 1±2. 9 years)، sprint (mean age ± SD: 32. 1±2. 5 years) and control (mean age ± SD: 32. 6±2. 6 years). Training program of resistance group was 8 weeks، 3 days per week، 5/5 set motion، 50-80 1RM) and sprint group was 8 weeks، 3 days per week، 5 times 10 m — 4 times 20 m — 3 times 30 m — 3 times 60 m — 2 times 100 m — 1 time 200 m and control group had no training during this period. Two blood samples were collected before and after the training period in order to measure ANP. Data were analyzed by SPSS 18، descriptive statistics، paired t test، one-way ANOVA and Tukey''s post hoc test at P≤0. 05. The results showed that the resistance and sprint training for eight weeks significantly increased plasma ANP (P≤0. 05). There was an insignificant difference in plasma ANP between resistance and sprint groups (P=0. 106) and a significant difference between the control group and two groups of resistance and sprint (P=0. 000). Based on the findings of the present study، it could be concluded that resistance and sprint training change the level of ANP hormone and that the beneficial effects induced by exercise training in healthy individuals might be due to changes in these parameters.

The aim of this study was to assess the effects of eight weeks of continuous running trainingand four weeks of detraining on lipid peroxidation (MDA) and anti-oxidative system response after an acute exercise session. For this purpose، 20 sedentary healthy males were randomly divided into two groups: experimental and control. At the beginning، before and after one acute exercise session، blood samples were taken to evaluate lipid peroxidation (MDA)، uric acid، bilirubin and total protein. Then، the experimental group was trained by continuous running three sessions per week for eight weeks while control group did not participate in any exercises during this period. After eight weeks، blood samples were taken again before and after an acute exercise session in order to measure the variables. After four weeks of detraining following eight weeks of exercise، experimental group participated in the third acute exercise session and blood samples were similarly taken in order to measure the variables. The results of one-way ANOVA with repeated measures indicated that lipid peroxidation (MDA) and uric acid significantly increased after one acute exercise session in the experimental group after eight weeks of exercise (P<0. 05). But، No significant differences were observed in bilirubin concentration and total protein after eight weeks of exercise (P>0. 05). Although significant increases were observed in lipid peroxidation (MDA) after four weeks of detraining (P<0. 05)، the changes in uric acid concentration، bilirubin and plasma total protein were not significant (P>0. 05). It can be concluded that eight weeks of continuous running training may create adaptation in anti-oxidative system and oxidative stress، but the effects of oxidative stress is reversed due to detraining.

The aim of this study was to describe and assess general anthropometric measurements and somatotypes of elite male players of Iran adult handball national team and to compare these measurements with those of European elite players in different positions. 19 elite handball players of Iran national handball team including goalkeepers (n=4)، wing (n=4)، center backs (n=2)، pivots (n=2) and backs (n=7) (mean age: 24. 42±3. 79 years، mean experience in national team 5. 88±3. 23 years) participated in this study. Anthropometric measurements including height، weight، body mass index، BF%، body fat content (6 and 8 points)، WHR and somatotypes of players were measured. The results showed that mean height of all players was 188±6. 6 cm which was lower than the mean height of European elite teams (188. 98)، mean weight was 91. 57±12. 98 kg which was more than the mean weight of European elite teams (86. 74)، mean BMI was 25. 76±3. 24 kg/m2، mean BF% was 9. 06±2. 65 which was lower than the mean BF% of European teams (9. 14) and players'' somatotype points (endomorphy، mesomorphy and ectomorphy respectively) were 2. 12، 5. 49 and 2. 36 which were different from European teams (2. 52، 4. 76، 1. 73). Also، anthropometric measurements of players in different positions were different; therefore، each handball position needs specific anthropometric measurements and somatotypes to which coaches and talent identification staff should pay special attention. In conclusion، Iranian elite handball players were heavier (about 5 kg) and shorter (about 1 to 3 cm) than elite European players. In addition، the somatotypes of Iranian players in different positions were different from elite Europeans teams.

The aim of the present study was to examine the effect of 8 weeks of resistance training and HMB supplementation on serum myostatin levels of non-athlete men. In this quasi-experimental study، 20 non-athlete men voluntarily participated in the study and were divided into experimental group (n=10، mean age 28. 75±1. 39 yr، height 179. 83±4. 30 cm، weight 81±5. 27 kg and BF% 28. 65±6. 40) and control group (n=10، mean age 28±2. 14 yr، height 180. 25±3. 71 cm، weight 84. 23±3. 58 kg and BF% 29. 21±5. 97). Both groups performed the 8-week resistance training protocol (5 sets، 3 sessions per week، 50-80% 1RM intensity). Experimental group ingested 3 gr of HMB daily while placebo was used in the control group. Fasting blood samples were obtained prior to the training and 48 hours after the last session of the training protocol. The results of independent t test revealed that HMB supplementation had no significant effect on serum myostatin level. The findings of this study leads to the conclusion that HMB supplementation has no significant effect on myostatin inhibition.