Effects of integrating self-efficacy strategies into multi-joint resistance exercise for overweight and obese older...

Obesity among older adults is increasing globally and contributes to functional decline, highlighting the need for interventions that address both physical and psychological barriers to exercise. However, it remains unclear whether embedding self-efficacy strategies within each session of progressive multi-joint resistance training provides added benefits beyond resistance training alone. This study examined the additional effects of integrated self-efficacy strategies on body composition (primary outcome) and secondary outcomes including blood biomarkers, physical function, and psychological measures in overweight and obese older adults. Thirty-four adults aged 60-75 years were included in the final intention-to-treat analysis and randomly assigned to a multi-joint exercise group (MJ; n = 16; age 67.63 ± 5.28 years; mean ± SD) or a multi-joint exercise plus self-efficacy group (MJS; n = 18; age 67.35 ± 3.69 years). Both groups completed a 12-week progressive resistance training program (60 min/session, three times/week). Outcomes were assessed pre- and post-intervention. Data were analyzed using linear mixed-effects models (intention-to-treat), testing group × time interactions with estimated marginal means and 95% confidence intervals (CIs). Both groups improved physical function (muscle strength, endurance, balance, and mobility), with no significant group × time interactions. For resting heart rate, the MJS group showed minimal change (Δ = 0.8 beats·min ⁻ 1), whereas the MJ group increased (Δ = 7.8 beats·min ⁻ 1), yielding a between-group difference in change of -7.0 beats·min ⁻ 1 (95% CI -12.5 to -1.9; p = 0.009). A significant group × time interaction was observed for HbA1c (p = 0.014); however, Bonferroni-adjusted pairwise comparisons did not demonstrate statistically significant within-group changes. Psychological outcomes improved more in MJS, including knowledge, self-efficacy, and outcome expectations. In conclusion, multi-joint resistance training improves physical function in overweight and obese older adults. Embedding self-efficacy strategies within training may provide additional psychological benefits and selected physiological benefits beyond exercise alone.