A Brief Overview of the Physiology of Stretching
Stretching starts in the sarcomere, the basic structural unit of a muscle. The sarcomere contains those famous myofibrils, actin and myosin. When a muscle is stretched, the area of overlap between the myofibrils decreases, allowing the muscle fibers to elongate. The muscle fibers are pulled to their full length, sarcomere by sarcomere. Additional stretching takes place in the surrounding connective tissue. The muscle and collagen fibers align themselves along the same line of force as the stretch. This helps to realign disorganized fibers (both muscle and connective tissue fibers) and contributes to rehabilitating scar tissue.