Toe Gap Force is Related to Ultrasonic Parameter of Calcaneus Bone Status in General Population

Elucidating the relation between bone health condition and muscle strength can provide useful knowledge for Japan's super-aged society. This study ascertained the Speed Of Sound (SOS) of the calcaneus and upper and lower limb muscle strength in a general population.

Medical examinations were conducted of 277 adult residents (100 men, 177 women; average age 67.1 years) of a mountain village. Bilateral hand grip and hand key pinch strength were measured. Hip abductor muscle strength was measured using a hand-held dynamometer. The pressure between the hallux and second toe (toe-gap force) was measured using a toe pressure measuring instrument. The Speed Of Sound (SOS) of the calcaneus was assessed using an ultrasound bone densitometer. Stepwise linear regression was used to identify the predictor of SOS using several factors as explanatory variables: gender, age, height, weight BMI, grip and key pinch power strength, hip abductor muscle strength, and toe-gap force in bilateral side. P values of < .05 were inferred as statistically significant.

Significant positive correlation was found between the SOS and each of bilateral hand grip and hand key pinch strength, hip abductor muscle strength, and toe-gap force in all participants. Stepwise logistic regression revealed gender (β coefficient= -0.32, p= .0001), age (β coefficient=-0.53, p= .000), height (β coefficient= -0.19, p= .03), and right toe-gap force (β coefficient= 0.11, p= .027) as predictors of calcaneal SOS for all participants.

Toe-gap force assessment might be more useful to predict calcaneal SOS than grip assessment in the general population.