Lower-extremity muscle forces measured by a hand-held dynamometer and the risk of falls among day-care users in Japan: using multinomial logistic regression analysis

Abstract

Purpose : To assess the relationship between the lower extremity muscle forces and risk of falls among the elderly who were using day-care services in the long-term care insurance system. Method : The study population comprised 96 women aged 69 v - v 91 years. At baseline, we assessed ADL, functional capacity, isometric muscle forces of knee extension and ankle dorsiflexion obtained with a hand-held dynamometer. After 1 year, we asked subjects about falls during the follow up period. Results : In univariate analysis, only the knee extensor strength ( p v = v 0.003) and ankle dorsiflexor strength ( p v = v 0.02) differed significantly according to the fall status. After adjustment for age using multinomial logistic regression analysis, the weak quadriceps group was 7.50 times more likely than the strong group to fall once ( p v = v 0.02), and 5.00 times more likely to fall twice or more ( p v = v 0.02). The weakest ankle dorsiflexor group was 5.09 times more likely than the strongest group to fall twice or more ( p v = v 0.05). Conclusions : Our results indicated that the forces of knee extensor and ankle dorsiflexor were strongly associated with falls among day-care users. Physiotherapy should focus on the lower-extremity muscle strength to prevent falls and deterioration of physical ability among elderly persons who are partially dependent and need support.