Tennis elbow is also known as lateral epicondylitis. In tennis elbow, the tendons that attach the forearm muscles to the outer part of the elbow degenerate, become inflamed and develop tears. Tennis players often irritate this area during backhand strokes. Anyone who uses a twisting motion is at risk including painters, carpenters, plumbers, cooks, weight lifters, and butchers. It may also develop by some who are constantly using a computer keyboard and mouse.