Tennis elbow is often an overuse injury. It occurs when the muscles and tendons in your forearm are strained due to a repetitive or strenuous activity.

Tennis elbow can also sometimes occur after banging or knocking your elbow.

If the muscles and tendons in your forearm are strained, tiny tears and inflammation can develop near the bony lump (lateral epicondyle) on the outside of your elbow.

You may get tennis elbow if your forearm muscles are not used to doing a certain activity, such as gardening or decorating. However, even if you use your forearm muscles frequently, you can still injure them.

Activities that can cause tennis elbow

You can develop tennis elbow by doing any form of activity that involves repeatedly twisting your wrist and using your forearm muscles. Examples include:

• playing racquet sports – such as tennis, badminton or squash (see below)
• throwing sports – such as the javelin or discus 
• using shears while gardening
• using a paintbrush or roller while decorating
• manual work – such as plumbing or bricklaying
• activities that involve fine, repetitive hand and wrist movements – such as using scissors or typing 
• other activities that involve repeatedly bending the elbow – such as playing the violin

Playing racquet sports increases your risk of developing tennis elbow, particularly if you play for the first time in a long time. However, despite its name, only five out of 100 people actually get tennis elbow from playing racquet sports.