Strength training stimulates predictable cardiovascular and neuromuscular responses. The cardiovascular responses result in nonpathologic concentric left ventricular hypertrophy with preservation of ejection fraction and no diastolic dysfunction. Resting heart rates and blood pressures in strength-trained individuals remain unchanged or decrease slightly. Strength gains occur from enhanced neuromuscular activation over the initial 8 weeks and from increased muscle fiber density and hypertrophy during subsequent weeks. Significant strength gains are possible in all populations, including children, women, and the elderly, when exposed to an adequate strength-training program. Strength training can also be a valuable adjunct in cardiac rehabilitation with the possible exception of patients with baseline abnormal left ventricular function.