Staying strong: strength and resistance training for older adults

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.

To allow physiological adaptation, it is important for the beginning exerciser to engage in a minimum of two resistance training sessions per week. All exercises should be performed through a painless range of motion. As these adaptations occur, the exerciser's range of motion and flexibility will gradually improve. Large muscle groups should be worked before progressing to smaller muscle groups. Be sure to start with lighter weights and higher repetitions (i.e., 1 to 2 sets of ! 0 to 15 reps). If any exercise causes unusual or extended periods of pain, it should be discontinued until its source has been identified. Personal trainers are encouraged to consult a physical therapist or physician to get advice on appropriate exercises for individuals with a chronic disease or disability.

Potential Benefits of Resistance Training

* Increased amount of Type II (fast-twitch) muscle fibers

* Increased size and strength of connective tissues (e.g., tendons, ligaments, fascia)

* Increased motor skill performance, the discharge frequency, synchrony, and amount of motor units recruited

* Increased lean body weight (muscle)

* Increased bone mass and density

* Decreased body fat percentage

* Increased balance, flexibility and strength.

Source: Bryant, C.X., Peterson, J.A. and Graves, J.E. "Muscular Strength and Endurance." ACSM9 Manual for Guidelines for Exercise Testing and Prescription--4th Edition. Philadelphia, PA: Lippincott Williams & Wilkins, 2001, pp. 460-467.

Resistance Training Guidelines

* Obtain a physician's approval before starting or resuming an exercise program.

* Do not exercise on an empty stomach.

* Drink plenty of water before, during and after training.

* Use extended warm-up and cool-down periods (i.e., 5 to 10 minutes).

* Always practice controlled breathing while lifting weights--do not hold your breath.

* All movements should be controlled and carried through a complete range of motion.

Methods to Achieve Resistance Training Overload and Progress

* Increase resistance or weight

* Increase number of repetitions

* Increase sets

* Decrease the rest period between sets or exercises

Source: Bryant, C.X., Peterson, J.A. and Graves, J.E. "Muscular Strength and Endurance." ACSM's Manual for Guidelines for Exercise Testing and Prescription- 4th Edition. Philadelphia, PA: Lippincott Williams & Wilkins, 2001, pp. 460-467.

Sample 1--Beginner Strength Training Program

Day 1
Leg Press
Machine Hip Adductions
Machine Hip Abductions
Machine Chest Press
Machine Upper Back Rows
Lying Crunches
Prone Back Extensions

Day 2
Single Leg Press
Machine Leg Extensions
Machine Hamstring Curls
Machine Chest Press
Lat Pulldowns
Opposite Knee Crunches
Prone Back Extensions

Sample 2--Intermediate Strength Training Program

1st Day
Dumbbell Squats
Stiff-Leg Deadlifts
Bench Press
Seated Hip Adduction
Seated Hip Abduction
Weighted Crunches
Feet Elevated Crunches

2nd Day
Seated Pulley Rows
Dumbbell Shoulder Press
Dumbbell Curls
Triceps Kickbacks
Alternating Crunches
Seated Rotational Twists
Alternating Superman

3rd Day
Step-ups
Standing Hip Adduction
Standing Hip Abduction
Lot Pull-Downs
Dumbbell Lateral Raises
Dumbbell Hammer Curls
Alternating Superman

Conclusion

Regular resistance training can have profound effects and positive changes in older individuals. Strength training can improve bone density, energy, metabolism, functional activity status and is an important aid in increasing physical activity levels in the elderly. Resistance training should be incorporated into all life-long physical activity programs.

References

A profile of older Americans- 1999 Washington: American Association of Retired Persons and Administration on Aging, 1999.

Bryant, C.X., Peterson, J.A., and Graves, J. E. "Muscular Strength and Endurance." ACSM's Manual for Guidelines for Exercise Testing and Prescription- 4th Edition Philadelphia, PA: Lippincott Williams & Wilkins, 2001, pp 460-467

Corbin, D.E. "Exercise Programming for Older Adults" ACSM's Manual for Guidelines for Exercise Testing and Prescription- 4th Edition Philadelphia, PA: Lippincott Williams & Wilkins, 2001, pp. 529-533.

Fiatarone, M., Marks, E., Ryan, N.D., et al. "High-intensity strength training in nonagenarians." JAMA, 263: 3030-3034, 1990.

Larsson, L. "Histochemical characteristics of human skeletal muscle during aging" Acta. Physiol Scand., 117: 469-471, 1983.

Mazzeo, R.S., Cavanagh, P, Evans, W.J., et al. "Exercise and Physical Activity for Older Adults." Medicine & Science in Sports & Exercise, 30: 992-1008, 1998.

McArdle, W. D., Katch, F.I., and Katch, V.L. Exercise Physiology: Energy, Nutrition, and Human Performance Philadelphia, PA: Lippincott Williams & Wilkins, 2001, pp. 878-880.

Nelson, M. E., M. A. Fiatarone, C. M. Morganti, I. Trice, R. A. Greenberg, and W. J. Evans. "Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures." JAMA, 272: 1909-1914, 1994.

Tracy, B.L., et al. "Muscle Quality. II. Effects of strength training in 65 to 75 year old men and women." Journal of Applied Physiology, 86: 195, 1999.

Ryan Thomas, C.S.C.S., is currently working on his Master} degree in Exercise Physiology and Biomechanics and is a strength and conditioning coach at California State University, Chico.

Scott O. Roberts, Ph.D., FACSM, FAACVPR, is an assistant professor in the Department of Physical Education and Exercise Physiology at California State University, Chico His primary area of expertise is Clinical Exercise Physiology. He has authored and co-authored 10 fitness and exercise science books and over a hundred articles and chapters in books Roberts has contributed three chapters to the Fitness: Theory & Practice textbook, authored two home study courses and contributed numerous articles to American Fitness.

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