Tennis elbow is a condition caused by inflammation of the tendons on the outside (lateral side) of the elbow at a bony prominence (lateral epicondyle) of the upper arm. Any repetitive movement of the wrist that requires excessive constant gripping or squeezing (like tennis, hedge clipping, excessive use of a hammer or screwdriver, painting etc.) can cause it. Treatment generally is with rest to the part, use of ice packs and pain-killers. If there is no relief, other treatment modalities are added.
An elbow strap or splint will help by taking the pressure off the inflamed tendon. You would also need to do physiotherapy at home so that there is an increase in flexibility and strength. The treatment has to be continued for the prescribed length of time as stopping prematurely increases the chance of re-injury to the tendon. Surgery is done if symptoms are present for more than 6-12 months despite non-surgical treatment. You need to cut down on the number of tourneys, wear your brace while playing and use a lighter ball.