The efficacy of high-load resistance training in combination with aerobic training in patients with coronary artery disease: a dose-dependent randomised, controlled clinical trial

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Slovenian Research Agency Background The combination of resistance training (RT) and aerobic training (AT) was shown to be superior compared to AT, although most studies applied only low-loads (LL) to moderate-loads in RT. Therefore, it remains to be elucidated whether high-load (HL) RT elicits greater improvement in maximal aerobic capacity and maximal muscle strength compared to low-load (LL) RT in combination to AT in patients with coronary artery disease (CAD). Purpose The aim of our study was to investigate the effects of HL-RT and LL-RT combined with AT in comparison to AT on maximal aerobic capacity, muscle strength and health-related quality of life. Methods We randomised 79 patients with CAD to HL-RT+AT (70 %-80% of one repetition maximum [1-RM]), LL-RT+AT (35%-40% of 1-RM) or AT group and 59 patients with mean (SD) age 61 (8) years and left ventricular ejection fraction 53 (9) % completed 12 weeks (36 training sessions) of the study. After the initial ambulatory screening by cardiologist and cardiopulmonary exercise test, patients were familiarised with proper lifting and breathing technique, and performed 1-RM test on leg press machine. During the training, the RT load progressively increased from 70% of 1-RM (6–11 repetitions per set) to 80% of 1-RM (6–8 reps per set) in HL-RT group and from 35% of 1-RM (12–22 reps per set) to 40% of 1-RM (12–16 reps per set) in LL-RT group in the first seven weeks of the intervention. Following re-evaluation of 1-RM, the training load in HL-RT group was progressed from 70% 1-RM (11 reps per set) to 80% 1-RM (6–8 reps per set), and the load in LL-RT group was progressed from 35% 1-RM (22 reps per set) to 40% 1-RM (12–16 reps per set). All patients performed AT consisted of 3-5 min of work-load interval cycling separated by 2 min of unloaded cycling progressing from 50% to 80% maximal workload achieved at baseline cardiopulmonary exercise test. We measured maximal aerobic capacity (VO2 max), maximal voluntary contraction (MVC) and quality of life at baseline and post-training. Results Exercise training was safe and associated with improvement in VO2 max (p < 0.01) in all training groups, whereas only LL-RT and HL-RT group improved MVC (both p < 0.001). Following training, VO2 max increased more in HL-RT group compared to AT group (+18 %, p = 0.032), and MVC increased more in HL-RT group compared to LL-RT group (+7 %, p = 0.018) and AT group (+16 %, p < 0.001). HL-RT group improved mental functioning component of short form 12-item quality of life questionnaire (+6 points, p = 0.003), with no significant difference compared to other training modalities. Conclusions RT on top of routine CR management, is safe and efficacious training modality for patients with CAD enrolled in cardiac rehabilitation.