Relationship Between Muscle Quality or Stiffness Measured by Ultrasonography and Range of Motion in Hospitalized Older Adults

Older adults who require nursing care have joint contractures characterized by limited range of motion (ROM). The present study investigated age-related muscle changes using ultrasonography and the relationship between ROM and muscle changes in older adults. Twenty-two healthy young adults (mean age: 23.3 y) and 60 hospitalized older adults (mean age: 86.1 y) participated. ROM of hip abduction was measured using a goniometer. Echo intensity (EI), reflecting interstitial fibrous tissue or fat within adductor longus (ADDl) was measured using B-mode ultrasonography, and strain ratio (SR), reflecting ADDl stiffness, was measured by strain elastography. The Mann–Whitney U-test and Spearman's correlation test were used for analysis. The ROM and SR of older adults were significantly lower than those of young adults (both p values <0.001). The EI was significantly higher in older adults than in young adults (p < 0.001). In older adults, the SR was moderately correlated with ROM (ρ = 0.49, p < 0.001). In conclusion, limited ROM and increase in interstitial fibrous tissue or fat and stiffness occur with aging, and the SR measured by strain elastography is useful for investigating the effect of muscle stiffness on the ROM of hospitalized older adults.