Tendons are the most common tissue affected. A tendon is the structure that attaches muscle to bone. If a tendon is affected the term commonly used is tendinits. Microtruama is damage to a tissue at the microscopic level. This usually is caused by repetitive loads to the involved tissue that is over the threshold of the ability of that tissue to heal.
Overuse injuries are more common as a population ages.
This is thought to be secondary to the stiffening of the tissue as one ages. However, overuse injuries can occur in any age group, and are becoming more common in children as their level of organized sport activity increases. Stress fractures occur when the bone is injured at a faster rate than the body can make new bone or heal the involved area. This is often seen in distance runners who overtrain. The rotator cuff is composed of four muscles that many help with shoulder rotation and stabilization.