Razi Journal of Medical Sciences

Background & Aims: One of the problems of old age is the decrease in muscle mass, which is called the gradual loss of skeletal muscle mass, strength and size of fibers, sarcopenia (4). This decrease in muscle mass is directly related to a decrease in anabolic hormones and an increase in catabolic hormones. Also, a decrease in growth factors involved in muscle growth has been observed during this period (5). On the other hand, with age, anabolic hormones and growth factors such as testosterone decrease. Also, with increasing plasma concentrations of catabolic hormones such as cortisol, tissue breakdown is another change observed with age, which causes changes in the neuromuscular junction (6). Therefore, researchers are always looking for a way to reduce the negative effects of aging and thus improve the quality of life of the elderly, and in this regard, various methods have been used. One of these methods is exercise and physical activity (7). One of the alternative training methods to high-intensity training, which due to its nature is not applicable and prescribed for some elderly people, is the use of low-intensity resistance training with limited blood flow. Some research shows that this type of exercise causes a similar increase in strength and muscle mass compared to traditional resistance training (10). Despite the above and reviewing research conducted in and outside the country, no research has been found on the subject and it is also found in adults, so the researcher seeks to explore the question of whether a period of resistance training and blood flow restriction Does it affect body fat percentage, muscle mass and testosterone to cortisol ratio in the elderly?
Methods: For the present quasi-experimental study, which was performed with a pre-test-post-test design, 45 men aged 60 to 70 years in Mashhad were selected voluntarily and after completing the consent form and medical-sports history to Randomly divided into three groups of 15: the first experimental group (resistance training without blood flow restriction) and the second experimental group (resistance training with closed blood flow, which was closed before the training of the proximal part of both thighs with a researcher cuff) and the control group. They were divided. Then, 24 hours before the start of the exercises, blood samples were taken from the subjects to collect data in the pre-test, and the subjects were introduced to the exercises, tests, and how to perform the movements correctly. Then, in order to perform the training protocol, first a maximum repetition of the subjects was measured in such a way that three days before the main resistance training program, the subjects first warmed up with light weights for 5 minutes and then according to the estimate. He himself selected the weights that the subject could do completely and correctly at least once and at most 10 times. By placing the amount of weight and the number of repetitions in Brzezinski's formula, the maximum strength of the subjects in the muscle groups was determined. To perform the resistance training program, the subjects were first introduced to the exercises and completed the consent form to participate in the research. The experimental groups then performed a weight training program three times a week in addition to their normal daily activities. The control group did not do any resistance training after the pre-test. Finally, 24 hours after the end of the 8-week post-test exercise program, all tests and blood samples were taken again (14).
Finally, from descriptive statistics (mean and standard deviation), Shapirovilk test to determine the distribution of data, one-way analysis of variance and Tukey post hoc test using SPSS software version 21 at a significant level (P <0.05) for Statistical analysis of data was used.
Results: The results showed that resistance training with limited blood flow had a significant effect on body fat mass and testosterone to cortisol ratio in older men. Also, the results of Tukey post hoc test showed that there is no significant difference between the resistance training group with limited blood flow and the resistance training group without blood flow restriction. However, there was a significant difference between the resistance training groups with limited blood flow and the non-restricted training group with the control group. Another finding showed that resistance training with limited blood flow has a significant effect on muscle mass in the body of older men (P = 0.001) and (F = 159.989). Also, the results of Tukey post hoc test showed that resistance group with limited There was a significant difference between blood flow and resistance training group without blood flow restriction (P = 0.001). (P = 0.001, P = 0.001)
Conclusion: The results of the present study showed that resistance training with and without restriction of blood flow decreased fat percentage, testosterone to corticol ratio and increased muscle mass in older men. In relation to the findings of the present study, we can mention the most common disorders of old age; Muscle atrophy is age-dependent or sarcopenia, in which muscle mass decreases by up to five percent each year (23). Aging is associated with significant changes in the axial regulation of hypothalamic-pituitary and glandular hormones. However, growth factors, myocain and cytokine have recently attracted the attention of many sports researchers (26). Anabolic hormones and their changes at this age are among the factors studied (27). Testosterone (28), and catabolic hormones such as cortisol, which increase with age and inactivity, and can directly and indirectly affect muscle mass (29).
On the other hand, many studies have reported that exercise is the best way to prevent and combat sarcopenia by improving the physiological function of skeletal muscle tissue. It seems that physical activity is currently the only intervention that reduces functional decline in the elderly (1). In this regard, research has reported that resistance activity in the elderly can improve physiological conditions, increase protein synthesis, increase strength, volume and muscle function, and hypertrophy in muscle fibers (31).
Another point that exists in low-limit resistance training is the change in muscle fiber recall. According to the principle of size under normal conditions in Katsu (BFR) training, even if the training intensity is not high, fast tension strings are called first (36). Research to address this phenomenon has considered that the availability of oxygen is greatly reduced after BFR training when a progressive recall of fast-twitch motility units occurs to compensate for defects in force development (34).