The evidence that tennis elbow is caused by poor muscle strength and improper tennis stroke is strong. The lesion may be at the lateral epicondyle (70 to 80% of patients), at the musculotendinous junction at the level of the radial head or, rarely, at the medial condyle. Anti-inflammatory steroid injections in the condylar lesions are helpful. Sinusoidal wave stimulation of the affected muscles, or repetitive active wrist dorsiflexion, is important in the early stages. The recurrence rate drops sharply when patients adhere to a progressive exercise program.