Muscle Strength Rather Than Muscle Mass Is Associated With Standing Balance in Elderly Outpatients

Abstract Objectives Assessment of the association of muscle characteristics with standing balance is of special interest, as muscles are a target for potential intervention (ie, by strength training). Design Cross-sectional study. Setting Geriatric outpatient clinic. Participants The study included 197 community-dwelling elderly outpatients (78 men, 119 women; mean age 82 years). Measurements Muscle characteristics included handgrip and knee extension strength, appendicular lean mass divided by height squared (ALM/height2 ), and lean mass as percentage of body mass. Two aspects of standing balance were assessed: the ability to maintain balance, and the quality of balance measured by Center of Pressure (CoP) movement during 10 seconds of side-by-side, semitandem, and tandem stance, with both eyes open and eyes closed. Logistic and linear regression models were adjusted for age, and additionally for height, body mass, cognitive function, and multimorbidity. Results Handgrip and knee extension strength, adjusted for age, were positively related to the ability to maintain balance with eyes open in side-by-side ( P = .011; P = .043), semitandem ( P = .005; P = .021), and tandem stance ( P = .012; P = .014), and with eyes closed in side-by-side ( P = .004; P = .004) and semitandem stance (not significant; P = .046). Additional adjustments affected the results only slightly. ALM/height2 and lean mass percentage were not associated with the ability to maintain standing balance, except for an association between ALM/height2 and tandem stance with eyes open ( P = .033) that disappeared after additional adjustments. Muscle characteristics were not associated with CoP movement. Conclusion Muscle strength rather than muscle mass was positively associated with the ability to maintain standing balance in elderly outpatients. Assessment of CoP movement was not of additional value.