The Effect Of Two Low-dose Strength/Balance Programs On The Physical Function Of Mobility-limited Older Adults

Abstract

BACKGROUND: Strength and balance training are critical to maintaining physical function and delaying the onset of major mobility disability in older adults (OAs). The minimum amount of this training required to yield clinically meaningful improvements in physical function is not clear. PURPOSE: To evaluate the effect of two low dose strength/balance programs on physical function in mobility-limited OAs. METHODS: Twenty community-dwelling OAs with mobility limitations were randomized to one of two strength/balance doses (n=10/dose), held 3x/week at a local YMCA for 10 wks. Eligible participants were ≥ 65 yrs of age, exhibited mild to moderate mobility impairment (short physical performance battery (SPPB) score of 3-9 out of 12), sedentary (<125 minutes/week of any kind of physical activity, determined by 7-day pre-baseline accelerometry), and had no major medical issues that would preclude exercise. Exercise doses were as follows: Low dose (L): 1 set each of chair stands, hip abduction, step-up and back with head turns, toe raises, and a balance stand). Higher dose (H): 2 sets of the previous mentioned exercises were performed. Each exercise had three variations of difficulty to accommodate different participant abilities and the number of reps were based on an RPE of 7 out of 10. Participants were assessed on SPPB score and 400m walk speed before and after the intervention by individuals blinded to which dose that participant was randomized to. Clinically meaningful improvements were defined as an SPPB improvement of 0.5 points and a 400m walk speed improvement of 0.05 m/sec. Data was analyzed using a t-paired test. Results are expressed as means (+ std deviation). RESULTS: SPPB score improved by 2.5 (+ 1.1) points among the entire cohort (p<0.001). Improvement was significant for each dose alone (L: 1.5 (+ 0.6), p<0.05), (H: 3.0 (+ 0.82), p<0.001). The improvement in SPPB score in the higher dose was significantly different from that observed with the lower dose (p<0.05). There was no significant effect of either dose on 400m walk speed. CONCLUSION: A 10 wk strength/balance program performed 3x/week and consisting of a single set each of select strength/balance exercises was sufficient to elicit clinically meaningful improvements in physical function for OAs with mild to moderate mobility limitations.