Causes
Tennis elbow is caused by overuse, strain or injury to the tendon that attaches to the bone on the outside of the elbow (lateral epicondyle). This tendon is attached to the muscle that bends the hand backwards from the wrist. This results in tiny, microscopic tears in the tendon that causes inflammation and pain in the tendon.
Tennis elbow can be caused by any repetitive movements that involves bending the wrist in a turning or backwards motion (e.g., tennis, painting, hammering, using a screwdriver). Pain often comes on gradually, but may be sudden such as after lifting a very heavy object. In some cases, no specific cause can be found.
Tennis players are more likely to develop tennis elbow if they have improper technique or are using an inappropriate racket handle size or racket weight.