When injury occurs, the normal healing process may be incomplete. This can be seen under a microscope by a deficiency of the cells called Fibroblasts. As a result small pain fibers transmit the pain impulse to the brain and an unconscious reflex causes the surrounding muscles to become tightened. The tightened muscles create more pain, as well as constrict blood supply (and thus restrict the body's natural transport mechanism which brings necessary repair factors to the area and remove debris and toxins) and a viscous cycle of pain, tightness and constriction ensues.
Prolo-therapy is a simple injection of special prolo-therapy solution at the site of injury. The injection starts a micro inflammatory process at the point of the injection. Inflammation kicks up the immune system and the immune system brings up fibroblasts (small cells that produce collagen). Where ever the small needle is placed and its solution injected, collagen growth is stimulated. You can think of prolo-therapy as jump-starting a flagging healing process with the intent to rebuild and repair injured connective tissue while decreasing pain.