There is increasing emphasis on the potential benefits of adding resistance training to an exercise regimen, especially for the elderly. These benefits may include increased bone mineral density, increased strength, and an increased ability to perform activities of daily living. For the elderly, these benefits of resistance training may, more importantly, result in additional advantages such as increased independence and decreased risk of falls and injuries.
The maintenance of bone mineral density levels is an important concern for postmenopausal women because they no longer have the protective effects of estrogen. Interestingly, although elderly women are more prone to bone loss, testosterone in men tends to have similar effects on bone remodeling, as does estrogen (Robergs & Roberts, 1997). Therefore, it is also important for elderly men to maintain their current levels of bone mineral density as testosterone levels decline with increasing age.
Numerous studies demonstrate strength training’s ability to increase bone mass, especially spinal bone mass. According to Keeton, a research study by Ontario’s McMaster University found that a year-long strength training program increased the spinal bone mass of postmenopausal women by nine percent. Furthermore, women who do not participate in strength training actually experience a decrease in bone density.
It is now well known through scientific studies that one of the best methods to maintain current bone mineral density is through physical activity. Activity increases the physical stresses on bone. These stresses help activate the osteoblasts and favor bone deposition (Robergs & Roberts, 1997).
The best bone builders are exercises that put force on the bone, such as weight-bearing activities like running and resistance exercises like strength training. In general, the greater the impact involved, the more it strengthens the bones.” However, it is important to distinguish the exercises that will increase bone density from the ones that will not. “Weightlifting, including curls and bench presses, is a beneficial activity … Dancing, stair-climbing and brisk walking are all weight-bearing exercises, which promote (good) mechanical stress in the skeletal system, contributing to the placement of calcium in bones. Aerobic exercises such as biking, rowing and swimming do not strengthen the bones,” writes Gary Null in Power Aging.
Not only is weight training safe, it is important for preventing osteoporosis. As muscles are pulled directly against the bone, with gravity working against it, calcium is driven back into the bones. It also stimulates the manufacture of new bone. This adds up to a decrease in the effects of osteoporosis by 50—80 percent.
A number of studies have shown that the most effective form of activity for increasing the physical stresses on bone, and hence improving bone density for those suffering significant bone density losses is High-Intensity Resistance Training. High-intensity resistance exercises, when properly progressed and supervised, are safe and beneficial activities for many elderly clients that improve musculoskeletal health and may reduce the likelihood of falling.
The most recent studies have shown that supervised high-intensity resistance exercise yielded greater increases in bone mineral density, lean mass, and muscle strength for both men and women than any other exercise. In addition, even the most elderly of clients can progress to high levels of intensity such as 70% of a 1 Repetition Max with safety.
There’s even some evidence that increasing muscle mass can increase bone mass. When researchers at McMaster University in Ontario put a group of postmenopausal women on a year-long program of anaerobic strength training, not only did their muscle size increase by 20 percent, but their spinal bone mass rose by 9 percent. It’s possible, then, that strength training might help ward off osteoporosis. Since stronger muscles do a better job of holding joints in their proper places, resistance training can lessen the joint wear and tear associated with osteoarthritis, the type of arthritis that most often afflicts older adults. What’s more, studies find, weight training can strengthen your bones, offering added insurance against osteoporosis. That’s because your bones and muscles are intimately connected. When you work your muscles against resistance, they pull on the bones they’re attached to. In medical lingo, your muscles exert stress on your bones, and your bones, under stress, respond by laying down more calcium to reinforce themselves.
Resistance Exercise and Bone Turnover in Elderly Men and Women.
This study showed that resistance training was successful for improving bone mineral density in the elderly and that the bone improvements occurred in direct proportion to the intensity of the muscular work. (http://www.researchgate.net/publica- tion/11574949_Resis- tance_exercise_and_bone_turnover_in_elderly_m en_and_women)
Strength training increases regional bone mineral density and bone remodeling in middle-aged and older men.
In this study, resistance training increased the Bone Mineral Density of untrained men. After just 12 weeks, their serum levels of osteocalcin had increased by an average of 19%.(http://jap.physiology.org/content/74/5/2478)
Effects of one year of resistance training on the relation between muscular strength and bone density in elderly women.
Forty-four women performed resistance training for one year. They made clinically significant improvements in strength, and their bone miner- al density improved in direct proportion to their muscular gains. (http://www.ncbi.nlm.nih.gov/pmc/articles/P- MC1724140/)
Bone mass in the calcaneus after heavy loaded eccentric calf-muscle training in recreational athletes with chronic achilles tendinosis.
Heavy-loaded eccentric calf-muscle training resulted in a fast recovery in all patients after achilles surgery. (http://www.ncbi.nlm.nih.gov/pubmed/10203422)
D.Nieman. (1998). The Exercise-Health Connection. Human Kinetics.
R.A. Robergs, and S.O. Roberts. (1997). Exercise Physiology: Exercise, Performance and Clinical Applications. Mosby.
Heidi M. Weingart, M.A. and Len Kravitz, Ph.D., Maddalozzo, G.F., and Snow, C.M. 2000. High-intensity resistance training: Effects on bone in older men and women. Calcified Tissue International, 66, 399-404.
Longevity by Kathy Keeton, page 160
The Bone Density Program George Kessler DO PC, page 279