Many factors contribute to a decline in strength as we age that might seem to prevent us from exercising. These factors — including the aging process itself, debilitating chronic illness, sedentary lifestyles and nutritional deficiencies — don’t mean that exercise must cease.

Physical frailty as we age isn’t inevitable. Research has proven that exercise for the elderly is productive and should be a component of a good health regimen no matter what the age.

In the past decade, much scientific research has been done on the benefits of resistance exercise for the elderly. One of the studies, involving frail elderly subjects at an average age of 89, concluded that the frail elderly can make remarkable improvement with a program of high-intensity exercise that includes resistance exercise training.

Resistance training, often called strength training for seniors, or weight training, is physical activity performed at a controlled speed using weights or an exercise machine. It works specific muscles that are not involved in aerobic exercise or endurance training — walking or jogging. The American College of Sports Medicine recommends a productive rate of resistance training at least twice a week, with an average of 12 repetitions in a set using a variety of resistance-based plans.

In another scientific study, the subjects were 100 male and female residents in a nursing home, including 38 who were age 90 or older. Most used a cane, walker or wheelchair, and 66 had fallen during the previous year. The resistance exercise program they embarked on wasn’t for wimps. The seniors worked out three days a week for 45 minutes with a series of exercises that began with one repetition and increased at each session.

The trial demonstrated that a high-intensity, progressive regimen of resistance exercise training improves muscle strength and muscle size in frail elderly people. Muscle strength was increased 113 percent. Gait velocity (walking speed) increased 12 percent. Stair-climbing improved 28 percent. Participants experienced an overall improvement in mobility and an increase in spontaneous physical activity.

Endurance training — walking or running — as contrasted with resistance training — exercising with weights and machines — is often not possible with persons who have lost mobility for a variety of reasons, including arthritic pain, fear of falling or difficulty moving from a seated to an upright position. But loss of mobility, having to use a wheelchair most of the time, does not rule out exercise. Resistance exercises are always possible and in some instances have built up muscle strength, loosened arthritic limbs and made some mobility possible. Four persons in the study who had previously used a walker required only a cane after the study was completed.

San Simeon residents and day care registrants are encouraged to participate in resistance training. Physical and occupational therapists direct the program, which includes workouts with equipment such as a NuStep, a total body exercise machine; a stationary bike; and weights.

You usually see exercise machines in television ads featuring muscular young men and women. Don’t be misled. Resistance training is just as effective and all-around health-promoting for persons at any age. Recently we have begun a yoga class at San Simeon. Yoga is a form of strength training in which your body is the resistance mechanism, and it’s an excellent complement to a program of resistance training. The health benefits of these exercises are scientifically proven.

Margaret DeVito is recreation director at San Simeon by the Sound Center for Nursing, Rehabilitation & Adult Day Health Care.