THE EFFECT OF EARLY FUNCTIONAL AMBULATORY ACTIVITIES ON EXPERIMENTALLY TENOTOMIZED ACHILLES TENDONS IN RATS (PHYSICAL THERAPY, THERAPEUTIC EXERCISE, REHABILITATION, SPORTS INJURIES)

The purpose of this study was to determine how functional ambulatory activities initiated at two different early time periods, namely day two to day four after surgery and day five to day seven after surgery, affect the tensile strength of experimentally tenotomized rat Achilles tendons as determined on the eighth post-operative day. Under aseptic conditions and pentobarbital anaesthesia, the right Achilles tendon was tenotomized, sutured and immobilized in 30 female Wistar strain rats. Ten rats were randomly assigned to each of three experimental groups by weight. The rats in group one were immobilized for four consecutive days after surgery, thereafter their splints were removed to permit functional ambulatory activities during the following three days. The group two rats received the same treatment (functional ambulatory activities) for the same number of days, but on post-operative days two, three and four. So that their experimental hindlimbs were immobilized on days, one, five, six and seven. The experimental hindlimbs of the animals in the third group (the control group) were immobilized continuously throughout the period of the experiment.;On the eighth post-operative day, the tensile strength of each experimental tendon was determined. The results showed that the mean tensile strength (13.85N) of the group one rats was significantly higher than that of the rats in group two (p < .001) or group three (p < .001). The mean tensile strength of the group three control rats (7.66N) though higher than that of group two rats (7.27N), did not differ significantly from the latter (p > .10). As was anticipated however, separation of tendon ends was more frequent in the group two rats than in the group three control rats. Tendon separation did not occur in the group one rats that had the highest tensile strength. Although most of the rats lost weight during the experiment, mean weight loss was significantly less in group one (p < .02) and group two (p < .025) than in group three control rats. There was no difference in mean weight loss between group one and group two rats (p > .10).