Everyone will have their day when they realize they have become one of the many considered to be elderly. For some it is a sad day because they believe the inevitable problems of age will soon strike them. The rest of the crowd comes to terms with it and understands that it is time to do what it takes to remain healthy in mind as well as body. It has been proposed that physical functioning may change as one grows older, but exercise helps prevent or reverse some of the disabilities or problems associated with aging. Exercising will help seniors ward off such common problems as fractures, strokes, arthritis, and osteoporosis.¹

Out of all the elderly problems, the most inevitable is probably osteoporosis. The large bone shafts in both men and women become more porous with age, but less osteoporotic change is seen in areas with the greatest mechanical stress. Taking a femur (thigh bone) for instance, the majority of the bone loss will come from the most anterior (front) and posterior (back) regions. In order to understand this more clearly, a closer look must be taken at the stresses upon the bone. The femur is constantly bombarded with bending forces that promote tensile stress in the lateral (outside) area and compressive stress in the medial (inside) area. Due to the side to side forces applied, the anterior and posterior regions are relatively stress-free, causing increasing bone loss and porosity.

Although the loss of bone that occurs in both male and female is equal, men compensate for a loss in bone strength with increased cross-sectional moment of inertia (CSMI) of the bone. Only in men does bone expand radially, which contributes greatly to strength in areas of porosity increase. Women are not so fortunate in the fact that a combination of losses in bone strength and shape are responsible for their higher incidence rate of fractures.

According to a study by Yeater and Martin, those suffering from osteoporosis in later life are not at a total loss.² An evaluation of bone and its relationship with muscle mass and strength, as well as physical activity support the idea that mechanical loads applied to the bone will stimulate bone formation. It was proposed that the weight of the muscle reflects the force exerted on the bone to which it is attached and concluded that muscle force is an important determinant of bone mass. The athletes with the highest bone density are weight lifters, but any physical activity with load and force transfers will act positively to density increase.

In the senior citizen population, fractures are common in osteoporosis victims. However, it is known from the facts above that exercise can benefit to improve skeletal mass by increasing muscle size and strength, even during the time of greatest bone loss.

The next question that remains is how well can the elderly build the muscle mass and strength required to induce bone growth. The answer to this comes from a series of studies that researched the area of muscle hypertrophy and adaptations in the elderly population.^3,4 The loss of muscle mass and strength is inevitable in older individuals just as bone, but the muscle limits their functional capacity. It is important for them to maintain as much strength as possible, not only for skeletal stability, but for the ease of everyday living requirements like walking endurance, lifting packages, and posture. A particular study looked at the effects of resistance training in the elderly for the upper extremity.³ After a period of a twelve week training program, it was found that elderly male individuals are capable of significant increases in muscle strength and size in the upper extremity as long as the intensity and duration of the resistance training program is sufficient.

Another study similar to the previous was performed to find muscle adaptations in elderly women.⁴ Due to the fact that women are less muscle-bound than males, it is interesting to find out if they are capable of improving muscularity in the later stages of life. The results of the study after several women were put through a twelve week resistance training program show that women can indeed produce significant gains in muscle hypertrophy as well as strength in their senior years. Although there were increases, they were not of the same proportions of those that can be reached by elderly males, but they were gains none the less. It is thought that the males experience higher gains in muscle hypertrophy and strength because they also go through a restoration of their neuromuscular recruitment patterns the women never had. Results such as these support the idea that resistance training of high intensity will produce gains high enough in magnitude to benefit elderly females with fragile bodies.

The benefit of a higher muscle mass and strength in an elderly person's body is that it can put more stress and force of both tensile and compressive nature on the bone in both the medial and lateral aspect which will help to promote bone growth in the areas most stressed. It is this skeletal mass build up that will decrease the effects of osteoporosis, which will have a direct effect on the lowering of fracture incidents in the aged community.

In conclusion, aging does not have to be the nightmare that many people make it out to be, as long as the individual is aware of his or her body and knows what they can do to better prevent the onset of crippling illnesses. It is best for them to exercise and build up bone, muscle, and most of all confidence in themselves that they will be alright.

References

1. Tanny, A. Longevity your never too old. Muscle and Fitness. 48, April 1994.

2. Yeater, R.A., R.B. Martin, Senile osteoporosis; The effects of exercise. Postgraduate Medicine. 75: 147-163, 1984.

3. Roman, W.J., J. Fleckenstein, J.Stray-Gunderson, S.E. Alway, R. Peshock, and W.J. Gonyea. Adaptions in the elbow flexors of elderly males after heavy-resistance training. J. Appl. Physiol. 74(2): 750-754, 1993.

4. Cherette, S.L., L. McEvoy, G. Pyka, C. Snow-Harter, D. Guido, R.A. Wiswell, and R. Marcus. Muscle hypertrophy response to resistance training in older women. J. Appl. Physiol. 70(5)_:1912-1916, 1991.

Daniel J. Kirages, D.P.T. works with outpatient orthopaedic, neurological, and urological disorders for Kaiser Permanente Los Angeles Medical Center in the Physical Therapy Department. He earned a Bachelor of Science degree in the field of Exercise Science, as well as a Doctor of Physical Therapy (DPT) degree at the University of Southern California School of Biokinesiology and Physical Therapy. He can be reached at dkirages@pacbell.net.