High-intensity strength training of patients enrolled in an outpatient cardiac rehabilitation program.

PURPOSE: This randomized controlled study assessed whether adding a program of high-intensity strength training (80% of maximum) to an outpatient cardiac rehabilitation program would be a safe and effective means of improving muscle strength and body composition. METHODS: Thirty-eight cardiac patient volunteers (29 men and 9 women) were randomized to either high-intensity strength training or flexibility training added concurrently to a 12-week outpatient cardiac rehabilitation aerobic exercise program. Muscle strength, local muscle endurance, joint flexibility, maximum treadmill tolerance time, and body composition were measured before and after completion of the training. RESULTS: The strength-trained patients (n = 18) had greater increases in mean strength (90 +/- 19% versus 9 +/- 4%, P < 0.0001) and local muscle endurance (20 versus 6 times, P < 0.0001), and decreases in mean perceived exertion for lifting the initial one repetition maximum load (11 +/- 1 versus 15 +/- 1, P < 0.0001) when compared with flexibility-trained patients (n = 16). The strength group lost more body fat (2.8 +/- 2.0 versus 1.3 +/- 2.0 kg, P < 0.01), tended to gain more lean tissue (1.5 +/- 2.3 versus 0.5 +/- 1.2 kg, P < 0.10), and had greater improvements in treadmill time (2.3 +/- 1.3 versus 1.2 +/- 1.0 minute, P < 0.02) than did the flexibility group. Improvements in joint flexibility were similar for each group. None of the subjects had evidence of cardiac ischemia or arrhythmia during the training sessions. CONCLUSIONS: Medically supervised high-intensity strength training is well tolerated when added to the aerobic training of cardiac rehabilitation programs and allows patients to aggressively gain the strength and endurance they will need to complete daily living tasks at lower perceived efforts. Strength training also reduces cardiac risk factors by improving body composition and maximum treadmill exercise time.

Effects of high-intensity strength training on quality-of-life parameters in cardiac rehabilitation patients.

Cardiac rehabilitation programs have not consistently been shown to improve the psychological well being of their patients. In our study of 38 cardiac patients (29 men and 9 women), a variety of quality-of-life parameters were assessed before and after they completed either 12 weeks of high-intensity strength training or flexibility training added to their outpatient cardiac rehabilitation aerobic exercise program. The strength-trained patients increased their self-efficacy scores for lifting (29% vs 4%, p <0.05), push-ups (65% vs. 17%, p <0.01), climbing (36% vs 0%, p <0.001), and jogging (100% vs -9%, p <0.001), when compared with the flexibility-trained patients. The strength group also had greater improvements in Profile of Mood States dimensions: total mood disturbance (123% vs 18%, p <0.05), depression/dejection (73% vs 15%, p <0.05), and fatigue/inertia (42% vs 3% p <0.05), than did the flexibility group. The Medical Outcome Survey Short Form 36 role emotional health domain scores were significantly improved in the strength group when compared with the flexibility group (64% vs 0%, p <0.05), and the role limitation scores improved in both groups. Increases in strength were associated with enhanced self efficacy and improved mood and well-being scores (n = 34, r = 0.30 to 0.53, p <0.05). High-intensity strength training added to a cardiac rehabilitation program of selected patients leads to improvements in quality-of-life parameters. These data, in conjunction with improvements in strength, strongly support the value of adding high-intensity strength training to cardiac rehabilitation programs.