INFLUENCE OF PHYSICAL EXERCISE ON AGING RATS .2. LIFELONG EXERCISE DELAYS AGING OF TAIL TENDON COLLAGEN

Regular physical exercise has been shown to have a number of benefits compared with sedentary behaviour, such as delaying a number of aging changes and increasing the life expectancy but not the maximum lifespa n. The purpose of this paper is to analyze the effects of physical exe rcise on the connective tissues of the body, especially systemic effec ts. We trained male Sprague-Dawley rats in a treadmill from the age of 5 months to 23 months. We analyzed the effects of training on tail te ndons with respect to thermal stability of collagen and biomechanical properties of tendon bundles. Although tail tendons are attached to mu scles, the are not weight-bearing as limb muscle tendons and can, ther efore, be considered to be subjected mainly to systemic effects. The t hermal stability of tail tendon collagen was significantly lower or 'y ounger' for the trained group compared with the sedentary one. The bio mechanical parameters were likewise 'younger' with respect to maximum stress, although considerably stiffer compared with a 5-month-old base -lint group. This suggests that there are several mechanisms, elicited by physical exercise, that act on the connective tissues. It can be c oncluded that life-long physical exercise has a beneficial influence o n the connective tissues of the maturing and aging organism.