عنوان مقاله [English]
Back ground and aim: Attention to physical activity as a complement to a healthy life has expanded, and scientific evidence for the health benefits of exercise is growing. Studies show that regular physical activity has significant benefits, and in addition, physically active people have a longer lifespan than inactive people. Achieving and maintaining physical fitness affects all aspects of life and in addition to strengthening health, is effective in increasing work and intellectual productivity and also benefits from recreational activities and leisure. Regular exercise and physical activity can reduce morbidity and mortality by reducing heart disease, diabetes, high blood pressure, cancer, depression / anxiety and overweight. It also protects the health of bones, muscles and joints . Due to today's jobs, which are often associated with inactivity, physical activity in leisure time and sports activities are recommended . On the other hand, in Iran, about 72.9% of women aged 25 to 34 do not have physical activity .
The method of the present study, in terms of time a prospective study, In terms of subject matter an applied research and in terms of method and strategy it is a quasi-experimental research. The present study population included inactive women in Tehran with an age range of 25 to 35 years. A total of 40 inactive women who had no history of any physical activity in the past year were randomly selected as a research sample and divided into two groups of control and experimental (20 people in each group). The training program consisted of 8 training sessions (two sessions per week) using park sports equipment such as back and forth stepping machine, Tusan machine and foot press machine. Data collection tools were Sargent power test, three-legged distance, star test balance test and single-leg jump time at a distance of six meters. To analyze the data along with descriptive statistics (mean and standard deviation, etc.) Kolmogorov-Smirnov test was used to examine the normal distribution of variables and analysis of covariance was used to examine changes in variables in SPSS software version 24.
Results: After removing the effect of pre-test, there is a significant difference between the mean scores of the two groups in the post-test of muscle function parameters; Therefore, exercises with park bodybuilding machines affect the muscular function of women's lower limbs.
Discussion and Conclusion: Explaining the results of the study, it can be said that in resistance training by park equipment, muscle stretching and hormonal changes, activate the cascading pathways of gene expression and proteinization, which in addition to metabolic changes, cause structural changes, especially in the myosin heavy chain. Increased muscle proteins eventually lead to hypertrophy or increase in fiber size and diameter, which is also directly related to increased strength . Accumulation of metabolites is believed to cause GH secretion from the pituitary gland, thereby increasing muscle growth . According to some research, the concentrations of growth hormone, norepinephrine and insulin-like growth factor (IGF-1) increase after resistance training. These mechanisms justify the hypertrophy resulting from resistance training in the aforementioned research. However, there are differences in different studies that can be related to the number and age of subjects, gender, type of exercise program including intensity and duration of exercises, number and type of movements performed, rest intervals and number of training sessions. Be per week. Increased balance in the experimental group can also be considered due to the activation of deep sensory receptors, preparation of motor neurons in a group of muscles and joints to perform movement, increased coordination and integration of motor units, all muscle contraction and increased inhibition of opposing muscles. Resistance training in the park affects the subjects' neuromuscular changes and improves and develops neuromuscular coordination. In resistance training, the individual needs more balance and benefits from the integration of deep sensory receptors and muscle coordination in co-contraction activities .
However, factors such as the strength of exercise that occurs in skeletal muscle in the first 4 to 8 weeks are due to the nervous system's response to increased load rather than to the hypertrophy of muscle fibers. Increased electrical activity of muscles during this period is due to increased excitation of motor units and increased frequency and coordination of nerve messages, which can lead to improved motor learning and muscle coordination. These changes appear to be due to decreased inhibitory function of the central nervous system on muscles, decreased sensitivity of the Golgi tendon, or changes in the neuromuscular junction of motor units. Considering that the training period of this study was eight weeks, it seems that the changes in motor function were due to the acute response of the muscles to the prescribed exercises. Although these changes can improve muscle function by increasing muscle strength and coordination, if a person stops exercising, it is likely that the changes will return to normal soon and muscle function will be challenged; Therefore, it is necessary for people who want to improve their muscle function with the help of the exercises of the present study to continue these exercises over time so as not to suffer from the complications of lack of exercise. Therefore, it is suggested that organizations and bodies related to sports and physical activity, by developing and expanding the sports equipment of the parks, provide the ground for the development of citizens' physical activity and improve their muscular function, and provide the necessary training in this field.