The effect of exercise and anabolic steroids on the mechanical properties and crimp morphology of the rat tendon.

The administration of anabolic steroids is believed to be widespread among athletes, but convincing evidence relating to the beneficial effect of such compounds on collagenous structures of the locomotor system is not available. Since it has not been possible to analyze relevant human tissue, an animal model was used to investigate the change in particular mechanical and morphological properties of rat tendon after a period of controlled exercise, with or without anabolic steroid supplementation. A significant difference (P less than 0.001) was found between the crimp angles and lengths of collagen fibrils and theoretical toe limit strains of the four groups under study. No other significant differences (P greater than 0.05) were observed. Controlled exercise and anabolic steroid administration produced the greatest change in crimp parameters and the largest theoretical toe limit strain. This implies that muscle contraction will be greater for a given stress and thus alter the normal biomechanics of limb movement. Further studies are required to determine more definitively the effects of anabolic steroids on a connective tissue such as tendon.