Responsividade de parâmetros neuromusculares e capacidade funcional a dose mínima de treinamento resistido em mulheres de meia-idade e idosas

Abstract

Resistance training (RT) is an effective strategy to mitigate the loss of muscle strength and the risk of functional limitations that occur drastically after 55 years of age. However, there is evidence of inter-individual variations in responsiveness to resistance training, since some people can be responsive and others non-responsive to the same protocol. Thus, the objective of the present study was to verify the responsiveness of middle-aged and elderly women submitted to TR with a minimum dose approach and to verify the effect of the protocol on muscle strength and functional capacity of the participants. Twenty-two untrained women, mean age 64.3 ± 7.2 years, body mass 65.5 ± 9.2 kg, and height 152.3 ± 4.3 cm, randomly assigned to the Intervention Group (INT), submitted to the minimum dose protocol during 4 weeks, or to the Control Group (CON), who participated in two lectures and two stretching classes. The participants were evaluated for strength (1 repetition maximum in Leg Press 180º, Seated Rowing, and Straight Supine) and functional capacity (Timed Up and Go, Physical Performance Battery) before and at the end of the 4 weeks. For the statistical analysis it was performed the Analysis of Variance of repeated measures and Bonferroni post-hoc test for data with normal distribution, Mann Whitney U test for non-normally distributed data, Deltas of variation (Δ%) to present percentage of change and independent t test to compare the means of percentage of change between groups. The significance level adopted was p< 0.05. Levene's test was used to check the variance between groups. For classification of responsiveness, the standard deviation of the CON change score was multiplied by 1.96. Individuals outside this range were classified as High responders or Low responders. The results suggest 16.6% High responders in the 1RM of the straight supine and 8.4% in the estimated 1RM in the same exercise, with 25% High responders for average and peak velocity of the Sit and Stand test. Regarding the mean differences, we observed significant increases in muscle strength only for INT, with no differences between groups. Thus, it is concluded that 4 weeks of TR performed with a minimal dose approach presents a small rate of High responders for upper limb strength and lower limb speed. Furthermore, the training dose used seems to be insufficient to generate greater muscle strength and functional capacity adaptations than the control in middle-aged and elderly women.