Efficacy of a theory-based and setting-based intervention in promoting strength training among older adults in Hong Kong: A clustered randomized controlled trial.

The present study aimed to examine the efficacy of an intervention, based on the Health Belief Model (HBM) and social support, in promoting strength training (ST) among older adults. A two-arm clustered randomized controlled trial (RCT) was conducted among 235 older adults from eight elderly centers in Hong Kong. The intervention group engaged in a 6-month intervention comprising ST sessions, exercise consultations, social gatherings, and a buddy program, while the control group participated in social gatherings. Assessments were conducted at baseline (Month 0), post-intervention (Month 6), and 3-month follow-up (Month 9), with primary outcome being the prevalence of meeting the American College of Sports Medicine (ACSM) recommendations of ST. Results showed that the intervention group reported significantly higher prevalence of meeting ACSM recommendations for ST at both post-intervention and follow-up. Linear mixed models showed significant interaction effect between condition and time on perceived susceptibility of sarcopenia and muscle strength and significant condition effect on self-efficacy for ST, perceived severity of sarcopenia, perceived barriers of ST, and intention to perform ST. Findings suggest that the intervention, guided by HBM and social support, improves older adults' ST participation, muscle strength, perceptions on sarcopenia, and self-efficacy for ST, which offers great potential for broader application in other settings.