Tennis elbow, quarterback shoulder, and jumper's knee are forms of tendonitis, a painful but often preventable injury.

Tendonitis is your body's way of telling you that you're putting too much stress on this muscle and joint.

Tendons are connective tissues that hold muscles to bones. When muscles contract, tendons react, causing bones to move.

Too much stress on joints can tear and inflame tendons, says the American College of Rheumatology. The tissue will fix itself quickly if the damage is slight or happens only sometimes. But pain can become constant if the damage happens often.

Weekend athletes know that tendonitis is a common result of overdoing it, especially when the body is out of shape.

Other factors contribute to tendonitis:

• Forceful or violent motions, such as pitching a fastball
• Unnatural motions, like serving a tennis ball
• Poor body mechanics or method when doing an activity like aerobics, lifting weights, or painting the ceiling

Often several of these factors may be involved at once.

Chronic tendonitis is a dull but constant soreness that feels worse when you first start to move. It then eases up as muscles get warmer.

Acute tendonitis is a sharper pain that may keep you from moving the joint. The pain may eventually go away. But it's likely to return if the stressful motion is repeated.

See your doctor if you think you have tendonitis. Your doctor may recommend the classic RICE treatment for pain relief: Rest the joint. Apply ice packs. Compress the area with an elastic bandage to ease soreness and inflammation. Keep the joint elevated.

Your doctor may recommend taking over-the-counter pain relievers, such as aspirin (in adults), naproxen, or ibuprofen. These may also help sore soft tissue. Talk with your doctor before taking any over-the-counter medicine for this condition, especially if this is the first time.

If your doctor gives you the okay, start exercising to strengthen the muscles around the sore joint within a day or two. Start with a long warm-up to reduce shock to the tissues. Then try lifting light weights or working with an elastic exercise band. Go easy at first. Then build as your strength increases. Stretching is also a vital part of treatment. Hold each stretch for 20 to 30 seconds and repeat 3 to 5 times.

A prevention program should replace bad habits with these methods that promote a healthy workout:

• Warm up thoroughly, gradually building the intensity level of your workout. Cool down after the session.
• Train for a new sport before you start it. Start building strength and flexibility in the muscles you will use a few weeks or months in advance.
• Learn the correct method and use the correct equipment for any exercise or activity. Work out regularly, not just once a week.