Efectos del ejercicio físico en la composición corporal de adultos sedentarios

Resumen

Background: Health care has been a permanent concern throughout history and one of the most important desires of society. Movement is the basic foundation of life, nonetheless, for a variety of reasons, contemporary human being develops a life free of regular physical activity, constituting one of the most important health problems today, determining the appearance of overweight, obesity and multiple chronic diseases associated. Sedentariness is directly related to cardiovascular diseases, osteoporosis, cancer and diabetes, among others, unlike physical activity that is related to positive aspects on health, greater longevity and life expectancy. Regular physical activity is an essential component of a healthy lifestyle, generating physiological, psychological and social benefits, affecting positively to individuals who practice it. Body composition has an important relationship with health and is commonly used for research in obesity, body growth, physical activity and health, among others. Programmed and expert-assisted physical training is one of the processes that individuals may choose to improve their physical condition, in a systematic, motivated and risk-free trend. Objectives: The main objective of the present dissertation is the evaluation of the effectiveness of a combined endurance-strength training program on the improvement of body composition in sedentary adults, which will be the basis of our primary hypothesis. Specific objectives include the identification of the anthropometric profile of the users of sports centers and the analysis of the effect of the intervention, mentioned in the main objective, on the reduction of total body fat, visceral fat as well as the increase of muscle mass and the effect that this program has on the different age groups and complexion. This study aims to contribute to improving the health of people, more specifically, those who opt for scheduled physical activity. It has been possible through obtaining information that allows to increase quality of exercise prescription, safety of users, and competencies of prescribers, motivating users towards the practice of exercise on a daily basis and, in, all in all, to contribute from our area of responsibility to increase the quality of life of population. Methodology: a biphasic study was carried out. In the first place, a cross-sectional descriptive study of the anthropometric profile of the users of the different centers in which the study was carried out was developed, which consisted of a sample of 250 individuals. Subsequently, a prospective, quasi-experimental, pre-test/pos-test study was conducted to evaluate the effectiveness of a combined strength-resistance program on the body composition over an experimental group of 54 participants. The studies were realized during years 2011 and 2012 in three sports centers of Madrid (Spain). This project follows the recommendations of the CONSORT guide for the randomized controlled experimental studies. The combined endurance and strength program applied to the experimental experimental group was considered as an independent variable. That intervention had a frequency of 2 sessions per week (with at least 48h rest between sessions) during 16 weeks. The approximate duration of the session was 80 minutes. Weight, subcutaneous fat folds, body circumference, body mass index [BMI], percentage of fat tissue, percentage of muscle mass and distribution of muscle tissue were considered as dependent variables. Moderating variables were also taken into account: age, sex, height, type of complexion, basal heart rate and bone diameters. The techniques used in the data collection were an initial questionnaire of sociodemographic and anthropometric data used in the first phase, a questionnaire of anthropometric data post-test, Par-Q questionnaire (ACSM, 2011) and Fitcomp software, in which the anthropometric data were included to obtain a profile of each user. For the analysis of data, a descriptive analysis of sociodemographic and anthropometric variables of the sample under study was started. The uni-varied analysis was carried out taking into account the characteristics of the scales of measurement of these variables. Likewise, the descriptive analysis of the experimental group was continued. To test the hypothesis, the T-Student test of comparison of means for related samples, multivariate contrasts intra/inter subjects, Anova of Repeated Measurements as well as the test of Scheffe´s Post-Hoc were accomplished. In order to identify differences in mean between variables, non-parametric Kruskal Wallis and Mann-Withney U tests were applied. Regarding ethical considerations, all the principles established by the Helsinki Declaration of the World Medical Association (WMA) on "Ethical Principles for Research in Human Beings" of 2008 as well as the current legislation on data protection have been applied. Results: in the sample of 250 people there are 96 overweight people, which is equivalent to 38.4%, and 29 people with obesity, 11.6. According to World Health Organization, 39% of people in the world are overweight and 13% of them are obese (OMS, 2015). In the experimental group, there were 54 participants (21.6% of the total) with abdominal pre-obesity and 34 participants (13.60% of the total) with abdominal obesity, representing 35.20% of people with a high risk of chronic health problems in the future. In the experimental group, there is a clear improvement of the body composition after the intervention with the combined program of strength and resistance in all measured parameters. Regarding weight, there were significant differences between the pre-test and the post-test (t = 4.88, p = 0.001), being lower in the posttest at an average of 2.14 kg. There is also a considerable reduction in fat folds and practically all body circumferences. The total fat percentage also decreased significantly between the pre-test and the post-test (t = 7.56, p = 0.001), being lower in the post-test by an average of 3.33%. In addition, a significant increase in muscle mass percentage between the pre-test and the post-test was observed in an average of 2.15% (t = -5.45, p = 0.001). Conclusions: Overall, combined endurance-strength training is highly effective in controlling body composition, as it contributes significantly to the reduction of total body fat and visceral fat. In addition, this intervention has a very positive effect on muscle mass increase, especially in the upper body.