What Parts of the Body Are Affected?

Tendinitis causes pain and tenderness just outside a joint. Some common names for tendinitis identify with the sport or movement that typically increases risk for tendon inflammation. They include tennis elbow, golfer’s elbow, pitcher’s shoulder, swimmer’s shoulder, and jumper’s knee. Some common examples follow.

Tennis Elbow and Golfer’s Elbow

Tennis elbow refers to an injury to the outer elbow tendon. Golfer’s elbow is an injury to the inner tendon of the elbow. These conditions can also occur with any activity that involves repetitive wrist turning or hand gripping, such as tool use, hand shaking, or twisting movements. Carpenters, gardeners, painters, musicians, manicurists, and dentists are at higher risk for these forms of tendinitis. Pain occurs near the elbow, sometimes radiating into the upper arm or down to the forearm. Another name for tennis elbow is lateral epicondylitis. Golfer’s elbow is also called medial epicondylitis.

Shoulder Tendinitis, Bursitis, and Impingement Syndrome

Two types of tendinitis can affect the shoulder. Biceps tendinitis causes pain in the front or side of the shoulder and may travel down to the elbow and forearm. Pain may also occur when the arm is raised overhead. The biceps muscle, in the front of the upper arm, helps stabilize the upper arm bone (humerus) in the shoulder socket. It also helps accelerate and decelerate the arm during overhead movement in activities like tennis or pitching.

Rotator cuff tendinitis causes shoulder pain at the tip of the shoulder and the upper, outer arm. The pain can be aggravated by reaching, pushing, pulling, lifting, raising the arm above shoulder level, or lying on the affected side. The rotator cuff is primarily a group of four muscles that attach the arm to the shoulder girdle/shoulder blade. The rotator cuff attaches the arm to the shoulder joint and allows the arm to rotate and elevate. If the rotator cuff and bursa are irritated, inflamed, and swollen, they may become compressed between the head of the humerus and the acromion, the outer edge of the shoulder blade. Repeated motion involving the arms, or the aging process involving shoulder motion over many years, may also irritate and wear down the tendons, muscles, and surrounding structures. Squeezing of the rotator cuff is called shoulder impingement syndrome.

Inflammation caused by rheumatoid arthritis may cause rotator cuff tendinitis and bursitis. Sports involving overuse of the shoulder and occupations requiring frequent overhead reaching are other potential causes of irritation to the rotator cuff or bursa, and may lead to inflammation and impingement.

Knee Tendinitis or Jumper’s Knee

If a person overuses a tendon during activities such as dancing, cycling, or running, it may elongate or undergo microscopic tears and become inflamed. Trying to break a fall may also cause the quadriceps muscles to contract and tear the quadriceps tendon above the knee cap (patella) or the patellar tendon below it. This type of injury is most likely to happen in older people whose tendons tend to be weaker and less flexible. Tendinitis of the patellar tendon is sometimes called jumper’s knee because in sports that require jumping, such as basketball, the muscle contraction and force of hitting the ground after a jump strain the tendon. After repeated stress, the tendon may become inflamed or tear.

People with tendinitis of the knee may feel pain during running, hurried walking, or jumping. Knee tendinitis can increase risk for ruptures or large tears to the tendon. A complete rupture of the quadriceps or patellar tendon is not only painful, but also makes it difficult for a person to bend, extend, or lift the leg; or to bear weight on the involved leg.

Achilles Tendinitis

Achilles tendon injuries involve an irritation, stretch, or tear to the tendon connecting the calf muscle to the back of the heel. Achilles tendinitis is a common overuse injury, but can also be caused by tight or weak calf muscles or any condition that causes the tendon to become less flexible and more rigid, such as reactive arthritis or normal aging.

Achilles tendon injuries can happen to anyone who regularly participates in an activity that causes the calf muscle to contract, like climbing stairs or using a stair-stepper, but are most common in middle-aged “weekend warriors” who may not exercise regularly or take time to warm up and stretch properly before an activity. Among professional athletes, most Achilles injuries seem to occur in quick-acceleration or jumping sports like football, tennis, and basketball, and almost always end the season’s competition for the athlete.

Achilles tendinitis can be a chronic condition. It can also cause what appears to be a sudden injury. Tendinitis is the most common factor contributing to Achilles tendon tears. When a tendon is weakened by age or overuse, trauma can cause it to rupture. These injuries can be so sudden and agonizing that they have been known to bring down charging professional football players in shocking fashion.