Are dose-response relationships of resistance training reliable to improve functional performance in frail and pre-frail older adults? A systematic review with meta-analysis and meta-regression of randomized controlled trials.

This systematic review with meta-analyses investigates the impact of resistance training (RT), using meta-regressions, on functional performance in frail and pre-frail adults aged ≥ 65 years to determine the key variables of RT. Ten randomized controlled trials involving 1303 participants were analyzed. Five studies assessed habitual walking speed (HWS), three studies evaluated performance in the timed-up-and-go test (TUG), three studies evaluated performance in the Short Physical Performance Battery (SPPB), and three studies assessed performance in the sit-to-stand test (STS). RT alone improved STS time and SPPB scores in frail and pre-frail older adults. RT improved STS performance (Effect Size (ES):- 0.536; 95% CI - 0.874 to - 0.199; p = .002) and led to a 2.261-point increase in SPPB performance (ES:1.682; 95% CI 0.579-2.786; p = .003). At least two weekly training sessions are required to increase SPPB scores, and three sessions seem to optimize the improvements. Higher training volume per exercise and volume per session reduce the gains in SPPB performance. We did not observe any association between different doses of RT and STS time improvements. RT alone positively influenced TUG performance only in community-dwelling older frail and pre-frail adults but not in institutionalized older individuals. RT alone did not improve the HWS compared to the non-active control group.

Obesity is associated with postural balance on unstable surfaces but not with fear of falling in older adults.

BACKGROUND: There are inconsistent findings regarding the relationship between body mass index (BMI), fear of falling and body balance, especially on unstable surfaces. OBJECTIVES: To investigate whether obesity is associated with worse postural balance and fear of falling in older adults. METHODS: A cross-sectional study was conducted with 201 older adults, classified as normal weight, overweight, or obese according to BMI. Postural balance was evaluated on stable and unstable surfaces on the Biodex Balance System platform under three visual conditions: with and without visual feedback and with eyes closed. Fear of falling was identified by a dichotomous question and the Falls Efficacy Scale. These data were compared between groups and included in adjusted multiple linear regression analysis. RESULTS: The study showed no significant differences (p > 0.05) in body oscillations on a stable surface between the three groups. On an unstable surface, the obese older adults exhibited body oscillations from 0.61° [95% CI 0.07, 1.30] to 1.63° [95% CI 0.84, 2.41] greater than those with normal weight in the three visual conditions. The obese older adults also displayed larger mediolateral oscillations with visual feedback (mean difference: 0.50° [95% CI 0.01, 0.98]) as well as greater global oscillations without visual feedback (mean difference of 0.82° [95% CI 0.18, 1.81]) and with progressive instability (mean difference: 0.80° [95% CI 0.05, 1.66]) than the overweight older adults. BMI explained from 6 to 12% of body swings investigated on unstable surface. Obesity was not associated with fear of falling. CONCLUSION: Obesity was associated with reduced postural stability on unstable surfaces but not with fear of falling in older adults.