Signs and symptoms of tendinitis tend to occur at the point where a tendon attaches to a bone and typically include:

• Pain often described as a dull ache, especially when moving the affected limb or joint
• Tenderness
• Mild swelling

Although tendinitis can be caused by a sudden injury, the condition is much more likely to stem from the repetition of a particular movement over time. Most people develop tendinitis because their jobs or hobbies involve repetitive motions, which put stress on the tendons.

Using proper technique is especially important when performing repetitive sports movements or job-related activities. Improper technique can overload the tendon — which can occur, for instance, with tennis elbow — and lead to tendinitis.

Risk factors for developing tendinitis include age, working in particular jobs or participating in certain sports.

Age

As people get older, their tendons become less flexible — which makes them easier to injure.

Occupation

Tendinitis is more common in people whose jobs involve:

• Repetitive motions
• Awkward positions
• Frequent overhead reaching
• Vibration
• Forceful exertion

Sports

You may be more likely to develop tendinitis if you participate in certain sports that involve repetitive motions, especially if your technique isn't optimal. This can occur with:

• Baseball
• Basketball
• Bowling
• Golf
• Running
• Swimming
• Tennis

Without proper treatment, tendinitis can increase your risk of experiencing tendon rupture — a much more serious condition that may require surgery.

If tendon irritation persists for several weeks or months, a condition known as tendinosis may develop. This condition involves degenerative changes in the tendon, along with abnormal new blood vessel growth.