Analisando a robustez das medidas de força muscular e desempenho físico em mulheres com mais de 40 anos: um estudo de confiabilidade teste-reteste e análise do efeito do treinamento de força com carga autosselecionada sobre o desempenho físico, força e massa muscular

Abstract

The decline in muscle mass and physical performance in women, especially after the age of 40 and during the menopausal transition, can lead to severe cases of sarcopenia. Therefore, there is a need for accurate assessments to identify individuals at risk and propose interventions such as strength training as an effective alternative. The challenge of adherence to training programs emphasizes the intolerance of exercise intensity. The dissertation's research objectives include investigating the reliability of strength and physical performance tests, as well as evaluating the effect of self-selected load protocols. Emphasis is placed on the importance of identifying responders beyond the minimum detectable measures to obtain reliable data on interventions in the health of women over 40. The first study was a cross-sectional study with a total of 113 women, with an average age of 58±11 years (82% postmenopausal). One-repetition maximum (1RM) tests were conducted for seven strength exercises: 45° leg press, bench press, leg extension, pec deck, wide-grip lateral pull-down, leg curl, and seated cable row, with a retest after 48 hours. The Timed-Up-and-Go, six-minute walk, and 30-second sit-to-stand tests were performed on the same day and retested after 72 hours. Test-retest reliability was assessed using intra-class correlation coefficients for consistency and agreement, and absolute reliability was assessed using the minimum detectable change based on the standard error of measurement. 1RM and performance tests demonstrated excellent reliability, although significant MDM values were observed, especially for the machine-based 1RM test. Despite excellent relative reliability, FM and DF tests showed low absolute reliability, particularly the machine-based 1RM and the 30-second sit-to-stand test. Changes in these tests smaller than the MDM may not indicate real alterations in middle-aged and older women. In the second study, a randomized clinical trial was conducted with 90 women over 40 undergoing two strength training protocols (ST) for 12 weeks. Initially, questionnaires on cognitive function (MOCA), physical activity (IPAC), quality of life (SF36), and sociodemographic aspects were administered. Before and after the intervention, DF tests (TUG, LS, 6MWT), muscle strength assessment (1RM), and body composition evaluation were conducted. After the initial assessment, participants were randomized into two groups: the traditional group (GT), which trained with an imposed intensity of 50-80% of 1RM, and the self-selected load group (GA), with autonomy to choose intensity. The self-selected intensity protocol proved effective for strength gain, muscle mass, and DF improvement. However, equivalence with the traditionally recommended ACSM protocol could not be established. Intensity was found to be an important variable for muscle strength gain, with volume being relevant for muscle mass responses. Moreover, responses beyond the MDC were influenced by both intensity and volume.