The fitness movement that began in the late 1960s and early 1970s centered {{U}}(31) {{/U}} aerobic exercise. Millions of individuals became {{U}}(32) {{/U}} in a variety of aerobic activities, and literally thousands of health spas developed around the country {{U}}(33) {{/U}} capitalize on his emerging interest in {{U}}(34) {{/U}} particularly aerobic dancing for females. A number of fitness spas existed prior {{U}}(35) {{/U}} this aerobic fitness movement, even a national chain with spas in most major cities. However, their focus was {{U}}(36) {{/U}} on aerobics, but {{U}}(37) {{/U}} weight training programs designed to develop muscular mass, strength , and endurance in their primarily male enthusiasts. These fitness {{U}}(38) {{/U}} did not seem to benefit financially from the {{U}}(39) {{/U}} fitness movement to better health, since medical opinion suggested that {{U}}(40) {{/U}} training programs offered few, if {{U}}(41) {{/U}}, health benefits. In recent years, {{U}}(42) {{/U}} weight gaining has again become increasingly popular for males and for {{U}}(43) {{/U}} females. Many current programs focus not only on {{U}}(44) {{/U}} muscular strength and endurance but on aerobic fitness as well.
Historically, most physical fitness tests have usually included measures of muscular strength and {{U}}(45) {{/U}}, not for health related reasons, but primarily {{U}}(46) {{/U}} such fitness components have been related to performance in athletics. However, in recent years, {{U}}(47) {{/U}} has shown that training programs designed primarily to improve muscular {{U}}(48) {{/U}} and endurance might also offer some health {{U}}(49) {{/U}} as well. The American College of Sports Medicine now recommends that weight training {{U}}(50) {{/U}} part of a total fitness program for healthy Americans.