The updated exercise guidelines of the American College of Sports Medicine now include strength training. Its experts now advise people to perform at least eight to 10 weight-training exercises for at least one set of eight to 12 repetitions. This routine should be performed at least twice a week. These updated guidelines reflect many of the recent research studies about the benefits of resistance training.
Reduced Body Fat
Loss of body fat is usually associated with aerobic exercise, but some studies indicate that weight training can play an important role in reducing fat and increasing lean muscle mass. Wayne Westcott, Ph.D. of the Quincy YMCA, performed research on this subject in 1991. The study involved 72 overweight volunteers, who were placed in two groups. Group 1 performed 30 minutes of aerobic exercise on a stationary cycle. Group 2 performed 15 minutes of exercise on the stationary cycle plus 15 minutes of weight training. The "aerobic-only" group lost a total of 3.5 lb. Three pounds was fat and a half pound was muscle loss. The "aerobic and weight-training" group lost 8 lb., with an actual fat loss of 10 lb. and an increase of 2 lb. of lean body weight.
Muscle Hypertrophy
Vivian H. Heyward, Ph.D., is a professor at the University of New Mexico. Her book, "Advanced Fitness Assessment and Exercise Prescription" explains how weight training increases muscle size. Weight training increases the size of the muscle's contractile protein, the size of the muscle fibers and the amount of connective tissue surrounding the fibers.
Bone Mineral Density
A January 14, 2003, news release for the American College of Sports Medicine cites a number of studies that show a relationship between weight training and bone density. The study was performed by researchers at the University of Arizona Departments of Physiology and Nutritional Sciences. Eight exercises were selected to strengthen the small- and large-muscle groups responsible for supporting the spine and hip. Over 140 postmenopausal women were recruited for the 1-year study. At the end of the year, most subjects showed an increase of bone mineral density, especially in the hip and thigh area.
Increased Strength
Weight training increases strength by training the body to recruit additional motor units. A motor unit is a motor nerve cell and the muscle fiber that it activates. Light exercise will cause the body to recruit the motor units that activate the slow-twitch or endurance fibers, whereas weight training recruits both the slow-twitch and fast-twitch fibers, which are responsible for quick bursts of energy.
Member Comments