Body composition, physical performance and muscle quality of active elderly women

Abstract

Fat gain is one of the major factors aggravating physical disability in the elderly population, which presents an increase in fat mass and a decrease in lean mass compared to the young population. For this reason it is important to assess body composition and the effects of these alterations in obese elderly women. The purpose of this study was to assess body composition, physical performance and muscle quality in active elderly women. Cross-sectional study included 75 elderly women (29 eutrophic and 46 obese) 65-80 years old. Body composition was evaluated by dual energy X-ray absorptiometry (DXA) and the physical performance was determined by 6-minute walk test (6MWT), handgrip strength (HS) and knee extension strength (KES). Muscle quality was calculated as the ratio between muscle strength and lean mass. Fat free mass, lean mass, fat mass and percent body fat were significantly higher in the obese group (p<0.05). Furthermore, the obese group showed a poorer performance than the eutrophic group in the 6MWT (432.31±66.13 m and 472.07±74.03 m, respectively, p=0.01). HS and KES did not differ between groups, however, regarding muscle quality, the obese group exhibited a impaired in comparison to the eutrophic group in the upper (11.45±2.57 kg and 13.31±2.03 kg, respectively, p<0.01) and lower limb (2.91±1.16 kg and 3.44±0.97 kg, respectively, p=0.05). The increase in muscle mass detected in the obese elderly was not sufficient to maintain adequate muscle quality and physical function, showing a negative influence of the excess of body fat.

Keywords: Aging; Muscle quality; Obesity; Physical performance.