Lower-extremity muscle force and balance performance in adults aged 65 years and older.

ABSTRACT

BACKGROUND AND PURPOSE: Measures of postural control may be useful for determining fall risk in older people and for determining the outcomes of treatments aimed at improving balance. Commonly used tools measure the output of the postural control system. The purpose of this study was to determine the degree to which one component of postural control (muscle force) contributes to scores on 3 functional balance measures. SUBJECTS: Fifty community-dwelling volunteers between 65 and 91 years of age (mean = 74.82, SD = 6.11) participated. Based on their histories, 11 subjects were classified as being at risk for falling. METHODS: Measures were the Berg Balance Scale (BBS), the Functional Reach Test (FRT), and the Timed Get Up & Go Test (GUG). The force generated by 12 lower-extremity muscle groups was measured using a handheld dynamometer. RESULTS: In the group reporting no falls, dorsiflexor and subtalar evertor force accounted for 58% of the score on the BBS, ankle plantar-flexor and subtalar invertor force accounted for 48.4% of the score on the GUG, and ankle plantar-flexor force accounted for 13% of the score on the FRT. Ankle dorsiflexor and hip extensor forces were lower in subjects reporting falls, and force of the ankle dorsiflexors predicted fall status. CONCLUSION AND DISCUSSION: Distal muscle force measures may be able to contribute to the prediction of functional balance scores; however, the muscles involved in the prediction differ depending on the measure of balance.