a. a. ravasi

The results of many researches show that plasma myostatin negatively regulates muscle mass. Therefore، the aim of the present study was to investigate the effects of aerobic، resistance and concurrent training programs on the plasma myostatin levels in overweight non-athletic men. In this semi-experimental research، 39 non-athletic students (range of age 18-27 years old and BMI between 25-30) voluntarily participated in this study and were randomly assigned to aerobic training (n=8)، resistance training (n=8)، concurrent training (n=12) and control group (n=11). Theexperimental groups performed their training protocol for 8 weeks and 3 sessions per week while control group did not participate in any training program. The training protocol of the resistance group consisted of 5 resistance exercises with weights at 50- 80% of 1RM، for aerobic group consisted of aerobic running with 65-85% HRmax for 25-40 min. and for concurrent group consisted of both resistance and aerobic training protocols. 5 mm blood was collected from antecubital vein of the subjects (in fasting state) before and 48 h after the last session of the protocol. The results of one-way analysis of variance (ANOVA) showed a significant change in myostatin between concurrent and resistance (p=0. 029)، control (p=0. 000) and aerobic groups (p=0. 000) and also between resistance and control groups (p=0. 044) but there was not a significant difference between aerobic and control groups (p=0. 919). Therefore، it can be concluded that resistance and concurrent training can be an effective way of preventing muscle atrophy and sarcopenia while muscle sarcopenia is more likely in aerobic training.

The aim of the present study was to investigate the effect of glucose and glutamine supplementation on two serum growth factors، GH and IGF-I، in non-athlete males during four weeks of exhaustive endurance - intermittent training that causes glycogen depletion.

20 non-athlete healthy males were selected and randomly assigned into four groups including: glucose supplementation with glycogen depletion training group (n=5، supplement 1)، glutamine supplementation with glycogen depletion training group (n=5، supplement 2)، glycogen depletion training group (n=5، placebo)، and a group without any treatment (n=5، control). The blood samples were collected at the onset of the training protocol، and 48 hours after final training session from anticubital venous. Serum GH and IGF-I concentration were determined by ELISA technique. The main and interaction effects of variables were determined using TWO WAY ANOVA compeleted with Tukey post-hoc test. The significant level was chosen as α=0. 05.

The results showed the significant effect of training variable for serum IGF-I concentration، (p<0. 01). Post-hoc test showed the significant difference between supplement 1 with control groups (p<0. 01)، and placebo with control (p<0. 01). The effect of training variable was not significant for serum GH concentration. In addation، the effect of supplementation variable was not significant neither for serum IGF-I، nor serum GH concentration. Also، the interaction effect between the two variables was not significant.

The results suggested that glucose or glutamine supplementation does not have significant effects on serum GH and IGF-I concentration after four weeks، but four weeks glycogen depletion training causes an increase on the serum IGF-I.

The purpose of this study was to determine the effect of dietary supplementation with zinc, magnesium and zinc plus magnesium on muscle strength in active women.

Forty active women selected randomly were randomly divided into 4 groups of 10 each, all undergonig resistance training and receiving, daily, a supplement of either zinc (50 mg zinc sulfate), magnesium (250 mg magnesium oxide), or zinc plus magnesium (50 mg zinc sulfate plus 250 mg magnesium oxide), or no supplement (control group). All the subjects had a history of sports activity. Blood samples were collected and 1-RM was measured at the beginning and after 8weeks.

Independent and paired-sample t-test showed that zinc, magnesium and zinc plus magnesium supplements had no statistically significant effects on the strength of lower body muscles. However, the magnesium supplement had a significant positive effect on the strength of upper body muscles (chest, back, as well as back and hand bending muscles). In addition, the zinc and zinc plus magnesium supplements affected significantly the strength of the back and hand bending muscles. Further analysis of the data showed that the zinc plus magnesium supplement had no significant effect on the serum zinc and magnesium concentrations.

Dietary supplementation with zinc, magnesium and zinc plus magnesium can effect desirably the upper body muscles strength in active women. Keywords: