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What Is Tendinitis?

Tendinitis is inflammation in or around a tendon, which is a band of fibrous tissue that connects muscle to bone and transmits the force and action of the muscle. Tendons are designed to withstand bending, stretching, and twisting, but they can become inflamed because of overuse, disease, or injuries that leave them with torn fibers or other damage. Tendinitis around the heel is known as Achilles tendinitis, and on the outside of an elbow it's called lateral epicondylitis, or tennis elbow.

The pain can be significant and worsens if damage progresses because of continued use of the joint. Most tendinitis heals in about two to four weeks, but chronic tendinitis can take more than six weeks, often because the sufferer doesn't give the tendon time to heal. In chronic cases, there may be restriction of motion of the joint due to scarring or narrowing of the sheath of tissue that surrounds the tendon.

What Causes Tendinitis?

Tendons can become inflamed when overstressed from any activity. Weekend athletes, who exercise sporadically rather than regularly, often develop sore tendons. But by far the most common cause is repetitive stress -- using the same joints for the same stressful movements again and again. This happens not only in sports but also in many types of office work and other situations. Tendons are also more likely to become inflamed with increasing age, because muscles and tendons tend to lose their elasticity over time.

WebMD Medical Reference

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