The Aging Athlete

Life Sp­­­­an:

The human organism has a fixed life span. This genetically determined, species-specific constant is best as a fixed number of normal cell replications. Once this normal number of cell cycles reached, abnormal changes within the cell occur with increasing frequency. Further the amount of time between cell division increases.

Life Expectancy:

            Life expectancy connotes a far different concept. It deals more closely with the influence of environmental factors on the organism. Hostile environmental factors diminish life expectancy whereas a conductive environment allows life expectancy to genetically approach the determined life span. As the life expectancy approaches life span in our society, quality of life issues become increasingly important. It is with these issues that the physical caring for the aging athlete must contend.

Aging Process:

Skeletal changes-   

The aging process is associated with predictable physiologic and biomechanical changes:   

• Decrease in bone mass.

• Decrease in cortical thickness.

• Increase in cross sectional diameter.

A decrease in bone mass can be measured in the normal human female by the time she reaches her mid-forties. Similarly, normal males show a measurable decrease in bone mass by the time they reach their fifties.

Factors that stimulates bone resorption & bone loss:

•         low serum calcium

•         high serum phosphate

•         inactivity (leads to disuse atrophy)

•         acidosis

•         steroids

The physiologic activity of bone throughout life is subject to a variety of imbalances. As a general rule, the normal aging process of males relates to a decrease in formation of bone in latter decades of life. Women, however, are subject to increased resorption of bone, particularly in the years surrounding menopause.

Factors that slow bone resorption & bone loss:

•         estrogen

•         alkalosis

•         high ratio of serum calcium to phosphorus

•         increased activity level

•         high clcium intake

Minimum adult requirement for dietary calcium:

·         Premenopausal women – 1000 mg/day

·         Postmenopausal women – 1500 mg/day

·         Lactating women – 2000 mg/day

·         Men – 1000 mg/day

To a certain extent, loss of bone mass is reversible. An increase in the level of activity, medication and dietary correction stimulates a measurable increase in bone mass in all age group.

Soft tissue changes:

            At all ages myotendinous junction is the weakest link in the muscle tendon unit and in its attachment to bone. Although the muscle tissue remains relatively homogenous and fails at an unpredictable location. “Disuse atrophy” diminishes the efficiency of the myotendinous unit and contributes to a loss of stiffness and to a decreased load to failure.

Physiological changes in Aging muscle:

·         A loss of motor units.

·         Decrease in number of muscle fibres.

·         Decrease in speed of contraction.

·         Increase in reflex time.

·         Slower relaxation phase of contraction.

·         Increased average collagen fibril size in tendon.

·         Increased insoluble collagen content and collagen cross linking in tendon (causes increased stiffness of the aging tendon).

·         Decreased tendon water, chondroitin sulphate and hyaluronic acid content.

·         Decreased capillary density.

Healing response:

            Vascular insufficiency, diabetes and a variety of other disease process results in delayed healing. The literature describing age related changes in skeletal and soft tissues has at least one major flaw. All studies even those that stratify patients according to age, fail to differentiate activity levels.