Tennis elbow is a common condition with a variety of causes outside of just playing tennis. What all of them have in common is that they result in overstraining the same area of the forearm, arm, or hand muscles. Tennis elbow is the result of tiny tears/inflammation in the tendon or tendon attachment in the elbow, and often occurs after repetitive motions of the wrist or arm, especially prevalent in those who are reliant on the computer mouse.