Effects of resistance training alone on exercise capacity and health-related outcomes in patients with coronary artery disease: a systematic review and meta-analysis

Resistance training is recommended as a component of cardiac rehabilitation for patients with coronary artery disease (CAD), but its independent effects remain uncertain because it is commonly combined with aerobic exercise or delivered within multicomponent rehabilitation programmes. To evaluate the effects of resistance training alone in adults with CAD, primarily compared with usual care or no structured exercise, and secondarily compared with aerobic or combined exercise training. We conducted a systematic review and random-effects meta-analysis of randomized controlled trials with a clearly identifiable resistance-training-alone arm. Outcomes were analysed separately according to comparator type. Post-intervention values were used for quantitative synthesis, and certainty of evidence was assessed using GRADE. Eighteen core randomized controlled trials contributed to the quantitative synthesis. Objective muscular-strength outcomes were available from only one exploratory trial, and no extractable muscle-mass outcomes were identified; therefore, these outcomes were summarized narratively rather than quantitatively. Compared with usual care or no structured exercise, resistance training alone improved peak VO 2 (5 studies; mean difference 3.29 mL/kg/min, 95% confidence interval 1.86 to 4.72; I 2 = 76.4%) and 6-min walk distance (6 studies; mean difference 79.06 m, 95% confidence interval 1.74 to 156.38; I 2 = 98.4%). No clear between-group differences were observed for peak VO 2 when resistance training alone was compared with aerobic training or combined aerobic plus resistance training. Evidence for body mass index, health-related quality of life, and safety was limited by heterogeneous or incomplete reporting. Certainty of evidence was low for peak VO 2 versus usual care or no structured exercise and very low for most other key outcomes. Resistance training alone may improve peak VO 2 and 6-min walk distance compared with usual care or no structured exercise in adults with CAD, but the magnitude of benefit remains uncertain because heterogeneity was substantial and certainty of evidence was low to very low. Comparisons with aerobic and combined exercise training showed no clear between-group differences, but the available evidence was insufficient to establish equivalence or support resistance training alone as a replacement for established aerobic or combined exercise programmes.