“What is best exercise for tennis elbow?”

Your occupational therapist can teach you isometric exercises. The best thing for a tennis elbow is to avoid rapid forceful extension of the elbow. Tennis elbow is a tear in the Muscle attachment of your extensor tendons to your humerus or arm bone. If this is from tennis then you need to learn proper Backhand technique; you should also avoid lifting objects with your elbow in extension. Instead you should lift objects from the ground in flexiion or using your flexor muscles that flex or bend your elbow.

To strengthen all the extensor muscles of the forearm.

Wrist extensor stretching and gentle strengthening. I recommend this be directed by a physical therapist who can utilize multiple modalities.

Exercises depend on the degree of involvement of the tendon. Better to get an evaluation from your orthopedic doctor. In general, stretching are required. But again, I would suggest evaluation by your doctor.

Tennis Elbow treatment is multifaceted.See my prior answer outlining Pain control,overuse control,and rehab physio exercise and occasionally surgery.There are multiple rehab resistance systems(such as free wgts,why machines,tension cords,twist devices etc.).The important aspect of physio rehab is gradualism focusing on wrist curls,wrist ulnar and radial deviation,elbow flexion&extension,and shoulder strengthening(the shoulder is often weak and is the foundation to the remainder of the arm).As noted in a previous answer concerning Tennis Elbow the details of non-surgical treatment is in book “Arm Care” Robert P.Nirschl M.D.,M.S. Medical Sports Inc. Arlington Virginia.

Check AAOS website for exercises.