This paper examines the effects of plyometric and resistance training on the explosive power and the amount of young male volleyball players' strength in Guilan province. The participants include 45 volleyball players, 15-22 years old, which were randomly divided into three groups: two training groups and one control group. Among the two training groups, one was engaged in plyometric and the other in resistance exercise training (six weeks, two times per week).The control group was doing its common volleyball training. Variables under measurement consist of strength and explosive power. We found that after a six weeks training, there were significant differences between the average of explosive power and strength in both groups of plyometric and resistance training in comparison to control group (P≤0.05). The researcher observed that there was a significant difference in the average of explosive power and strength within both plyometric and weight groups from pre to post-test (p≤0.05). The amount of improvement in resistance training group was more than plyometric group.

Background: Ghrelin and obestatin are some effective peptides for regulating energy balance, which investigating them change caused by physical activity are important. The objective of this research was to evaluate the effect of eight weeks of aerobic exercise on plasma ghrelin and obestatin of obese and overweight women. Material and Methods: This quasi-experimental research was conducted in Rasht in 2018. In this research, 24 obese and overweight subjects were selected and randomly divided into two groups of aerobic exercise (N = 12) and control (N = 12). The aerobic exercise group performed an aerobic exercise program for 8 weeks in three sessions of 60 to 70 minutes. Acylated ghrelin, obestatin and body composition of the subjects were measured before and after 8 weeks. Data were analyzed by using SPSS software and T test. Independent t-test revealed no significant difference between the levels of plasma ghrelin, Results: The results showed that after an aerobic training period there was no significant difference between the two groups in the levels of ghrelin and obstatin (p > 0.05), However, BMI showed a significant decrease in aerobic training group (p < 0. 05). Conclusion: In conclusion, this exercise regimen had a positive effect on reducing BMI which is related to Slight changed ghrelin and obstatin responses over time. This finding lends support for a role of exercise in Nervous systems that stimulated some anabolic hormones such as ghrelin and abstatin and it can change relationship between ghrelin, obestatin and some body composition indexes.