hello there, welcome to healthcare magic, thanks for your query. well tennis elbow is caused to an inflammation of common extensor muscles in the forearm, and it is caused due to the excessive, aggressive,inappropriate movements of forearm. the strap which has been given to you is called tennis elbow splint which has to be applied properly.. many people apply it in a wrong place and its of no use if you do so, tennis elbow splint should not be applied on the tender point but around 4 centimetres down the tender point on forearm and the round globular part should be on extensor surface of forearm. and it has to be applied 24 hours in a day till pain subsides may be for 2 to 3 weeks , you have to go for physiotherapy like ultrasonic therapy to the tender point, you should defer form swimming for atleast a month because you have to give rest to your forearm muscles, along with anti inflammatory drugs twice daily for 2 weeks , if pain doesn t subside then a steroid injection may be given to the tender point on your elbow, i hope this solves your queries, if u have any other doubt feel free to contact me on hcm. http://www.summitmedicalgroup.com/media/db/relayhealth-images/xtennis2_3.jpg