Document Type : Research Paper
Authors
Department of Exercise Physiology, Faculty of Sports Sciences, Isfahan University, Isfahan, Iran
Abstract
Background and Purpose
Obesity is one of the biggest public health challenges of the present century, such that today the health sector of most countries in the world is struggling with issues and complications resulting from the increasing incidence of obesity. Insulin-like growth factor-1 (IGF-1) is an anabolic hormone produced primarily by the liver as a result of interaction with growth hormone. In addition to the liver, IGF-1 is also produced in most extrahepatic tissues and acts as an endocrine, autocrine, and paracrine growth factor to regulate cell growth. Obesity is associated with chronic inflammation, which contributes to insulin resistance (IR) and type 2 diabetes. Insulin resistance impairs the ability of muscle cells to take up and store glucose and triglycerides, leading to high levels of glucose and triglycerides in the circulation. IR is increasingly common in all individuals, including middle-aged, overweight, and sedentary individuals. Exercise Training plays an important role in metabolic health, particularly in the insulin-like growth factor-1 system, and may be an alternative treatment for controlling changes in IGF-1 metabolism. Regular exercise can also improve insulin signaling in muscle. improve skeletal muscle mass and increase insulin sensitivity. Therefore, the aim of this study was to investigate the effects of 12 weeks of resistance training and EMS training on IGF-1 levels, insulin, glucose, insulin resistance, and body composition in overweight men.
Materials and Methods
The sample of the present study was made up of 40 overweight men with a BMI between 25 and 29.9. The age range of the subjects was between 30 and 50, and they had no regular physical activity during the past 6 months. The subjects were divided into 3 groups: EMS training (n=15), resistance training (n= 13), control (n=12) were divided. The exercises were performed for the resistance training group with an intensity of 50% to 85% of a maximum repetition and for the EMS training group as a pressure perception (master) with a value of 70% to 85%. In this study, an effort was made to control the volume and number of sets and repetitions in each session so that the amount of work done in both groups was approximately equal, despite the difference in intensity percentage, and therefore the impact of the difference in intensity on the results was minimized. Participants were asked to report their exercise intensity using the Borg Rating of Perceived Exertion (RPE) scale. The intensity of both EMS and resistance training was adjusted to achieve approximately equal RPE scores across both groups. The exercises were performed 3 days a week for 12 weeks. The training time in each session was 40 minutes. Also, they completed a three-day food diary form and a personalized meal plan was designed for each of them. Fasting blood samples were taken 48 hours before the first training session and 48 hours after the last training session to measure serum IGF-1 levels and insulin resistance. Blood sampling was done in two stages (pre-test stage and post-test stage). To measure IGF-1 factor, a DRG brand kit made in Germany with a sensitivity of 9.75 ng/ml was used by ELISA method. Blood glucose was measured using a ParsAzmoun company kit with a sensitivity of 5 mg/dl, and blood insulin levels were measured using ELISA method and a human kit (Beta Biomed) made in the USA with a sensitivity of 0.11(u IU/mL), and insulin resistance was measured using the homeostasis model assessment method (HOMA-IR) Body composition and anthropometric variables were examined in both pre-test and post-test stages using the XContact -356 body analyzer made by Jawon Medical Company, South Korea
Findings
The results showed that in the subjects of the three resistance training, EMS and control groups, there was a significant difference between the mean IGF-1 (P=0.001, F=30.7) at different time points (pre-test, post-test) in the groups. Also, according to the results of the between-group effects of IGF-1 in the subjects of the three resistance training, EMS and control groups, there was no significant difference in the mean IGF-1 (P=0.44, F=0.82) between the groups after 12 weeks of training.The mean IGF-1 in the resistance and EMS groups increased in the post-test compared to the pre-test, so that the EMS group increased by 14.07% and the resistance group increased by 11.82% compared to the pre-test. The results of insulin, glucose, and insulin resistance showed that in the subjects of the resistance training, EMS, and control groups, there was a significant difference between the mean insulin (P=0.001, F=42.09), glucose (P=0.001, F=13.9), and insulin resistance (P=0.001, F=48.5) at different time points (pre-test and post-test) in the groups. Also, according to the results of the between-group effects of insulin, glucose, and insulin resistance in the subjects of the three resistance training, EMS, and control groups, there was no significant difference in the mean glucose (P=0.29, F=1.28), insulin (P=0.13, F=2.1), and insulin resistance (P=0.11, F=2.3) between the groups after 12 weeks of training. The mean insulin, glucose, and insulin resistance in the resistance and EMS groups decreased in the post-test compared to the pre-test, so that after 12 weeks of training, insulin decreased by 17.6% in the EMS group and 19.4% in the resistance group compared to the pre-test, glucose decreased by 9.4% in the EMS group and 7.92% in the resistance group compared to the pre-test, and insulin resistance decreased by 25.9% in the EMS group and 25.5% in the resistance group compared to the pre-test. In addition, in all three resistance training, EMS and control groups, there was a significant difference between the mean percentage of fat, weight, skeletal muscle weight, and soft tissue weight at different time points (pre-test and post-test) in the groups (P≤0.05). However, there was no significant difference in the mean percentage of fat, body weight, skeletal muscle weight, and soft tissue weight between the groups after 12 weeks of training (P≥0.05).
Conclusion
In summary, the results of the present study showed that both resistance training and EMS significantly increased IGF-1 levels, but this increase was greater in the EMS group. In addition, in both groups, glucose, insulin, and insulin resistance levels decreased, and body composition improved in overweight men. Overall, given the positive results of EMS, it seems that this new training style can be considered an alternative or complement to resistance training.
Article Message
EMS training may be an effective training method in increasing IGF-1 levels and improving insulin resistance in overweight men compared to resistance training.
Ethical Considerations
This research has been approved by the Research Ethics Committee of Isfahan University with code IR.UI.REC.1403.028
Funding
This study received no funding from public, commercial, or nonprofit organizations.
Authors’ Contributions
All authors contributed to the design, implementation, and writing of all sections of this study.
Conflicts of Interest
The authors declared no conflict of interest.
Acknowledgement
This article is derived from the thesis of the Professional Doctoral Course in Exercise Physiology at University of Isfahan. We would like to extend our sincere gratitude to all those who contributed to the successful completion of this research.
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