EXERCISE PROGRAMS FOR OSTEOPOROSIS

It is widely accepted and documented that regular physical exercise appears to have a reduced risk of osteoporosis and delay the physiological decrease of bone mineralization density that begins around the age of 30 years in women and 40 years in men. Physical activity is thought to provide the mechanical stimulus or "loading" important for the maintenance and improvement of bone health. In addition to its skeletal effects, exercise improves overall physical fitness, muscle strength, coordination and balance. Exercise across the life span should be encouraged in order to maximize peak bone mass, reduce age related bone loss, and maintain muscle strength and balance. Evidence from cross-sectional and longitudinal studies have shown that women with greater muscle strength and muscle mass have higher BMD measurements. Women who have been able to maintain higher levels of physical activity have a 36% lower incidence of hip fractures than sedentary women.

Weight bearing is a key factor in the development and regulation of bone strength. Mechanical loading, muscular activity and gravity stimulate the bone cells to differentiate and grow. Bones bend or temporarily deform when a force is applied to the bone. The extent of that deformation is measured as strain and depends on the magnitude and direction of the force, the distance from the point of application of the force to the axis of bending, and the moment of inertia of the bone. Regulation of bone strength is a function of the mechanical forces or loads to which the bones of the skeleton are exposed. Studies have shown that women who walk 7.5 miles a week or more have higher bone mass density of the whole body, legs, and trunk, than women who walk less than 1 mile per week. Postmenopausal women who exercise for 30 minutes at 75% to 85% of maximum heart rate three times a week on a treadmill are able to attenuate the postmenopausal rate of bone loss; and exercising for 45 minutes at the same intensity level results in a slight net gain in bone mass. The Centers for Disease Control currently recommends at least 30 minutes of moderately intense activity on most days of the week. The beneficial effect of exercise on BMD is rapidly lost if the intensity and frequency of exercise diminishes and a sedentary lifestyle is resumed. In one study, six months of decreased activity in previously exercising women resulted in a reduction in vertebral bone mass from a 6.1% value above pre-exercise levels to a 1.1% value above pre-exercise levels.

Resistance training in the elderly has also been found to have an effect on BMD. Resistance training appears to have a more site-specific effect than aerobic exercises on maintenance of bone mass. Following a year long, high intensity resistance training program in women over age 65, significant increases in femoral neck and lumbar spine BMD have been noted.

Strength training has positive effects on muscle mass in the elderly as well. Progressive strength gains have been noted in the elderly up to ages 96 - 100. Increased muscle strength helps improve functional status, increase activity levels, counteract weakness and decrease physical frailty thereby reducing the risk of falls and osteoporotic fractures. An even greater reduction in the risk of falls is noted when balance training is included in the exercise program.

Multifaceted exercise programs have been found to reduce the risk of falls in the elderly. Exercise programs should be as individualized as possible, but group exercise sessions are beneficial in promoting adherence to the program. The exercise program should include components for flexibility, strengthening and balance training skills. Flexibility exercises include stretching in both sitting and standing. Strengthening exercises for the upper and lower extremities can easily be performed using elastic bands designed specifically for exercises. Weight bearing exercises should be performed for 30 to 45 minutes on a daily basis. A walking program is an excellent way to increase weight-bearing activities. Exercises to correct postural deficiencies and increase shoulder and pelvic girdle stabilization should also be included in the program.

Balance training is an essential component of the program. The majority of falls among the elderly are thought to be due to postural disturbances. Fifty percent of falls are thought to be due to sudden motion of the base of support such as slips and trips, 35% due to external displacement of the body's center of mass, and only 10% are attributed to spontaneous falls related to physiological episodes such as dizziness. Previously, balance was viewed as resulting from a distinct set of reflex-like equilibrium responses elicited by stimulus of a particular sensory system. Recently however, balance is viewed as a skill that the nervous system learns to accomplish using many systems, such as passive biomechanical elements, all sensory systems, muscles, and many different parts of the brain. Examples of activities used in balance training sessions include sitting and standing weight shifting; sways; forward, backward, heel-toe, lateral and braiding gait patterns; static standing with head or trunk movements; stand and reach; walking at different speeds; walking with head movements; ascending and descending stairs and ramps; physioballs; and use of dynamic surfaces such as foam, balance boards, air pillows, etc. These types of activities stimulate all systems the body uses to maintain and control balance. The exercise training sessions focusing on improving balance should include dynamic tasks that involve multisegmental control; sensory, motor and cognition components; inter-limb coordination; and coordination between the lower extremity and upper-body movements.

One of the most important aspects of the treatment program is establishment of functional goals. There should also be a strong emphasis on patient responsibility and independence in the home program. Most treatment protocols consist of 2 to 12 visits, depending on the severity of the osteoporosis, level of pain, and loss of mobility or function. Medicare guidelines recommend these sessions be completed within 31 days. Home exercise programs should include flexibility, weight bearing, strengthening, posture and balance exercises. Patients should also be instructed in proper posture and body mechanics to prevent injury during ADLs. Often, treatment is needed for pain control and soft tissue or joint dysfunction. When appropriate, patients may be referred to community or gym exercise classes. Fracture prevention is the primary goal in treatment of osteoporosis.