Staying strong: strength and resistance training for older adults

American Fitness, Sept-Oct, 2002 by Ryan Thomas, Scott O. Roberts

Our nation is aging at a rapid pace. Between 1990 and 1998, the number of people over the age of 65 increased 10 percent, while the population under 65 increased only 8 percent. As is evident with this large older population, life expectancy is increasing. An individual born in 1997 will live approximately 76.5 years--about 29 years longer than someone born in 1900.

Many factors can extend a person's life and independence. One of the best tools to enhance a person's quality of life is regular exercise including resistance training. The American College of Sports Medicine, American Heart Association, Centers for Disease Control and Prevention, American Association of Cardiovascular and Pulmonary Rehabilitation and the Office of the Surgeon General recommend regular resistance training be a component of an individual's fitness program.

The aging process has many physical consequences, including decreased resting metabolism, muscle strength and bone density as well as loss of muscle mass, impaired balance and increased body fat. Two of the most problematic consequences are muscle mass loss and rapid body fat increase. In adulthood, the average basal metabolic rate (BMR) declines 2 to 3 percent per decade. Increased body fat is typically the result of declining metabolic rate, muscle mass loss and lowered physical activity level. Preventing muscle mass loss and drop in metabolic rate are the most powerful benefits of participating in a regular resistance training program. Numerous studies confirm regular endurance and resistance training can preserve and even increase resting metabolism as we age.

Muscular Changes with Training

Significant declines in muscle mass, close to 50 percent, occur between the ages of 20 and 90. The decline is most dramatic in Type II (i.e., fast-twitch) muscle fibers. Sedentary young men have an average 60 percent of Type II fibers, which decrease to below 30 percent after the age of 80. This correlates directly to age-related decreases in strength and resting metabolism. An approximate 30 percent decline in strength occurs between the ages of 50 and 70, which can be directly attributed to Type II muscle fiber atrophy. These types of changes are typical in sedentary individuals.

Several studies demonstrate that when provided with adequate training stimuli, older individuals show similar or even greater strength gains than younger individuals. In a relatively short amount of time (i.e., two to three months) increases in strength levels can double or triple. Heavy resistance training appears to have a profound anabolic (i.e., protein stimulating) effect in older adults and, in combination with additional food intake, can result in muscle growth. Sufficient dietary protein intake is needed to facilitate muscular maintenance and growth, which is often lacking in older adults. According to the American College of Sports Medicine's position statement, "Exercise and Physical Activity for Older Adults" (June 1998), for proper nitrogen balance, the recommended daily protein intake is 1.0 to 1.25 grams of high quality protein per kilogram of body weight.

The Effects of Resistance Training on Bone Density

Muscle mass loss may also contribute to bone density reduction. For this reason, the importance of employing strength training as a means of preserving as well as increasing muscle mass and strength in sedentary elderly individuals should be realized. Loss of muscle mass and bone mineral density greatly increase the risk of falling--a major health concern among the elderly. Having weak muscles or balance problems contribute to falls. However, exercises which improve strength, balance and coordination reduce the risk of falls and fall-related injuries.

The effects of resistance training can counteract typical age-related declines in bone health by maintaining or increasing bone mineral density and total bone mineral content. Strength training also improves balance and physical activity levels, which can dramatically reduce the risk of fractures in people with osteoporosis. Moreover, regular exercise and strength training can provide positive improvements in measures of pain, disability and physical performance in individuals afflicted with osteoarthritis. These changes are greater than the traditional pharmacological or nutritional practices which maintain or slow the rate of bone loss, but do not aid the ability to improve muscle mass, balance and strength.

Modes of Resistance Training

With increasing age and varying fitness levels, it is important for individuals to consult their physicians prior to beginning or resuming an exercise program. Once clearance has been authorized, it is imperative to receive proper instruction from a certified exercise professional. In many instances, using tubing or one's own body weight can be sufficient when starting out. Machines also serve as excellent starting points for beginners and allow for an accelerated learning curve.

Once a base of muscular skill, strength and coordination has been established, gradual progressions in weight and repetitions should be made on a regular basis to maintain overload. Multi-joint exercises are preferred since they assist in the development of muscular fitness and strength. If possible, exercises should be performed in a standing position due to the added benefits of working against gravity on bone density.