Age-related changes in muscle elasticity and thickness of the lower extremities are associated with physical functions among community-dwelling older women.

Aim: To clarify the age-related changes in muscle elasticity or thickness of the lower extremities in older women, and to analyze their relationship with physical functions.

Methods: The muscle elasticity and thickness of the rectus femoris and medial head of the gastrocnemius of 102 young women (young group) and 221 elderly women (elderly group) were measured using ultrasonography. In the elderly group, physical functions, including knee extension strength, Timed Up and Go test, single-leg standing, maximum gait speed and Four Square Step Test were also measured.

Results: The elasticity of the rectus femoris and medial head of the gastrocnemius were significantly higher, but the muscle thickness of both muscles was significantly lower in the elderly group than in the young group (both P < 0.001). In the elderly group, the elasticity of the rectus femoris was significantly correlated with Timed Up and Go test, maximum gait speed and Four Square Step Test (ρ = 0.481, r = -0.387 and ρ = 0.401, respectively, all P < 0.001), and the medial head of the gastrocnemius was similar (ρ = 0.471, r = -0.489 and ρ = 0.422, respectively, all P < 0.001). The muscle thickness of the rectus femoris was significantly associated with knee extension strength (r = 0.444, P < 0.001).

Conclusions: Older women showed age-related changes in high elasticity and atrophy of the rectus femoris and medial head of the gastrocnemius. The high elasticity of both muscles, not muscle thickness, was associated with dynamic balance and walking ability. Geriatr Gerontol Int 2019; 19: 61-65.