Mudanças no desenvolvimento temporal da força em mulheres de diferentes faixas etárias

Abstract

Introduction: reduction in strength and reduction in speed of muscle contraction are the two major causes of functional impairment in the elderly. Objective: to examine age-related changes in the temporal development of the force of the handgrip and knee extensors in women. Methods: the sample consisted of 52 women subdivided in three groups (JO. n=24, 25.2±3.7 years; MI. n=13, 58±4.2 years; ID. n=15, 71.3±3.9 years). Tests of handgrip and knee extension were performed. Three attempts of maximum isometric effort were performed in each test, and the curve with the maximum strength value was selected for analysis by means of an algorithm developed using MATLAB®. The fat free mass (FFM) was assessed by Dual-energy X-ray absorptiometry. Results: we observed similar values in strength (p=0.831) and FFM (p=0.207) of the upper limb. The rate of the force development (RFD) was lower in the initial periods of muscle contraction (0-50 and 0-100ms) in the MI group (p = 0.005 and p = 0.000 for 50ms and 100ms, respectively) and ID (p = 0.003 p = 0.000 for 50ms and 100ms, respectively). The FFM and lower limb strength were lower in the MI group (p=0.006, p =0.014, respectively) and ID (p<0.000, p=0.000, respectively) compared to the JO. Already, the RFD of the knee extensors was similar in the MI group (p>0.05), but lower in the ID group (p<0.05) compared to the JO in all analyzed intervals. Conclusion: the results of this study demonstrate that the muscle groups of the upper and lower limbs are affected in different magnitudes by the aging process. The differences between limbs may be related to the quantity and quality of physical activities.