Overuse of the forearm muscles using a repeated twisting motion is the most common cause of tennis elbow. These movements are common to various jobs, such as carpentry or plumbing, and to many daily activities, such as yard work and lifting objects. Racquet sports, swimming, and throwing sports (such as baseball) can also lead to tennis elbow.
Tennis elbow injuries can result from:
Overuse. Repeated movements that involve twisting of the elbow cause small tears in the tendon, weakening it. Overuse depends on how hard or how long you do something.
Technique, or the way you do an activity. This includes holding equipment or a tool in a awkward position while you use it.
Equipment. This can happen, for example, if you use a tool or sports equipment that is too heavy for you or that has a grip that is the wrong size for your hand.
A single accident, such as a direct hit to the side of the elbow (lateral epicondyle), or falling on an outstretched arm.