Lower limb muscle best predictor of functional capacity in active postmenopausal women
Functional capacity (FC) in active postmenopausal women depends more on lower limb muscle strength than on abdominal obesity, suggesting that those with abdominal obesity may not necessarily have a reduced FC as long as lower limb muscle strength is preserved, according to a study.
The study included 44 active women (>7,500 steps/day) aged between 50 and 70 years. Assessments included body composition and distribution (dual-energy X-ray absorptiometry), FC (chair-stand, alternate-step and one-leg-stance tests), handgrip strength and knee extensor strength (dynamometry), steps/day (accelerometer) and cardiorespiratory function (spirometry/VO2max).
Results showed no correlation between body composition or body mass index and FC score. However, FC score significantly correlated with waist circumference (p=0.024), handgrip (p=0.036), knee extensor strength (p=0.003) and VO2max (p=0.006).
Additionally, when the highest FC quartile was compared with the lowest one, a significant difference in knee extensor strength (p=0.003) was observed. Knee extensor strength was also the only variable inserted into the FC prediction equation derived from the stepwise regression model (p=0.003).
The correlation observed between waist circumference and FC among active postmenopausal women confirms that an association exists between abdominal obesity and FC even in older women practicing physical activity daily, researchers said.
“However, it contradicts [previous reports] demonstrating that waist circumference is a reliable index to predict functional capacities, because our study did not demonstrate that waist circumference has a predictive capacity with regard to physical function in nonsedentary older women,” they added.
Researchers pointed out that waist circumference was not significantly associated with the chair-stand test and the alternate-step test score, but rather only with the one-leg stance test. This implies that abdominal fat accumulation might affect the centre of gravity and, therefore, balance to a greater extent than muscle strength and power required to stand from a chair or to climb stairs.
“It can be argued that women practicing physical activity spontaneously do more functional exercises that simulate activities of daily living than specific training aimed at improving balance,” researchers continued.
More studies with a larger battery of tests to determine FC, as well as mobility, are needed to confirm the present data, they said.