Exercise and its influence on aging in rat knee joints*.
The interaction between natural aging and exercise in the knee joints of 38 female Wistar rats, 14 of which performed treadmill exercise for 6 or 12 months was assessed. Qualitative morphological changes observed with age in joint tissues other than cartilage of sedentary and exercised animals were similar. Chondrocyte counts were only significantly different between groups of young and older control animals in the lateral tibia1 condyle with older animals having a higher median than younger control animals. Defects in the articular cartilage were observed in animals of all ages and in both groups; however, exercised animals showed a significantly higher frequency and greater severity of defects than age-matched sedentary animals. The interaction between exercise intensity and age-related changes in the rat warrants further investigation since these observations suggest exercise may increase microtrauma to the articular cartilage. J Orthop Sports Phys Ther 1986;8(6):310-319.
Walker
J M
JM