Background:
The benefits of cardiac rehabilitation (CR) are well established for men and women with cardiovascular disease (CVD). Resistance training (RT) during CR has been shown to improve the performance in strength-related activities of daily living (ADL) in men. Few studies have examined RT in women with CVD. For women, ADL may require strength more than endurance; thus women may stand to benefit the most from RT during CR. The relationship between RT and outcomes such as physical and psychological well-being may be mediated by changes in perceived self-efficacy (SE). The purpose of this study was to compare changes in SE, strength and exercise capacity in women after four-months of either combined aerobic-RT or aerobic-only training during CR.
Methods & Design:
We conducted a randomized controlled trial of aerobic-only (AT) or combined aerobic-resistance training (ART) in women (n = 92) after coronary artery bypass graft surgery (CABG; n = 58) or myocardial infarction (MI; n = 34). Exercise prescriptions were based on the American College of Sports Medicine guidelines. Women attended exercise classes 2x/week for six months. Both groups completed a 2-month run-in period of aerobic training prior to separation into treatment groups. RT was initially prescribed at 30-50% of one-repetition maximum (1RM), progressing to 70% by 4 weeks of RT. Total exercise time was equal for both groups. Outcomes were: SE (Lift, Walk, Stair, ADL), exercise capacity (peak VO2, KPM, METs) and strength (1RM) for arm flexion, bench press, leg press, and leg flexion. Outcomes were assessed upon entry to CR, after 2-months of aerobic training and again at discharge (6-months).
Results:
Groups were comparable with respect to demographic characteristics, SE, exercise capacity and strength at study entry. SE, exercise capacity and strength improved in the ART and AT groups after 2 (P < .05) and 6-months of CR (P < .05). Although improvements in strength occurred in both groups, there were significantly greater improvements in the leg press (P = .018), bench press (P = .003) and leg flexion (P < .0001) in the ART group. Statistically significant improvements (P < .0001) in SE for specific activities were observed in both the ART and AT groups respectively as follows: Stair (18.5% and 22.4%), Lift (50.7% and 24.4%), Walk (25.9% and 27.7%) and ADL (2.6% and 4.2%). There were no between group differences. Exercise capacity increased 22-34% in both groups (P < .0001). At 6-months SE and strength were significantly correlated. In both ART and AT, the relative changes (2-6 months) in bench press correlated with SE for lifting (r = 0.270; P = .02) and ADL (r = 0.295; P = .01) whereas the change in leg flexion correlated with SE for lifting only (r = 0.286; P = .014).
Conclusions:
CR is associated with improvements in SE in women regardless of the form of exercise training. Since SE and strength are correlated, resistance training may add an important dimension to women's rehabilitation programs.
Section Description
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