This study compared three different treatment approaches for lateral epicondylitis (tennis elbow), a common condition that causes pain on the outside of the elbow.Twenty-seven patients diagnosed with lateral epicondylitis were randomly assigned to one of three treatment groups for 6 weeks:Group 1 - Blood Flow Restriction Exercise (BFRE): Patients performed wrist strengthening exercises using light weights (30% of their maximum capacity) while wearing a pressure cuff on the upper arm that partially restricted blood flow. Sessions were held twice per week under supervision, along with daily stretching exercises and a wrist orthosis.Group 2 - Eccentric Exercise: Patients performed slow lowering (eccentric) wrist exercises using heavier weights (70% of their maximum capacity) five times per week under supervision, along with daily stretching exercises and a wrist orthosis.Group 3 - Orthosis Only: Patients wore a wrist orthosis that held the wrist in a slightly extended position throughout the day and performed daily stretching exercises at home.The main goal was to determine whether blood flow restriction exercise could reduce pain and improve hand function more effectively than eccentric exercise or orthosis use alone. Pain levels, hand grip strength, finger pinch strength, and upper limb function were measured before and after the 6-week treatment period.The study was conducted at Dokuz Eylül University, Department of Orthopedics and Traumatology, İzmir, Turkey.