Muscle thickness contribution to sit-to-stand ability in institutionalized older adults

Ultrasound is a low-cost, safe and accessible tool to use on muscle mass assessment. The relations between muscle thickness and lower limb function have not been investigated in institutionalized elderly people.

The purpose of the present study was to investigate the associations among sit-to-stand capacity, ultrasound-measured rectus femoris muscle thickness, hand grip strength and anthropometrics in a population of institutionalized older adults.

Twelve older adults (nine women and three men, mean age ± SD 86 ± 7 years, body mass index 24 ± 3 kg/m²) participated in this cross-sectional study. Sit-to-stand capacity using five-repetition sit-to-stand test, rectus femoris muscle thickness using B-mode ultrasonography, handgrip and anthropometric were measured. The relationships of the variables were analyzed using Pearson correlation coefficient and multiple linear regression analysis.

Significant bivariate correlations were found between rectus femoris muscle thickness and sit-to-stand test (p < 0.05). Multiple linear regression analysis showed associations between rectus femoris muscle thickness and sit-to-stand test, after adjusting by body mass index and age (p < 0.0001).

Rectus femoris thickness in contraction adjusted by body mass index and age was predictors of physical performance. The independent variables shared 78.6% of variance in the sit-to-stand test.

Rectus femoris muscle thickness measured with ultrasonography, body mass index and age could explain functionality in institutionalized older adults measured by five-repetition sit-to-stand test.