The Science of Tennis Elbow
Tennis elbow involves degeneration of the tendons on the outside of your elbow, primarily the extensor carpi radialis brevis. Despite the name, it's rarely from tennis. The tendon develops small tears and becomes disorganized rather than inflamed. Repetitive gripping and wrist movements overload the tendon beyond its capacity to repair, leading to pain and weakness. Similar to golfers elbow (medial epicondylitis), tennis elbow is a degenerative tendinopathy rather than an inflammatory condition, though it affects the opposite side of the elbow and involves different movement patterns.
Contributing Factors
Poor wrist and grip mechanics are the primary drivers of tennis elbow. When you grip objects with your wrist bent back (extended) rather than in a neutral position, you place massive stress on the extensor tendons at your elbow. This is exactly what happens during computer use when you rest your wrist on a pad while typing, or when gripping tools with your wrist cocked back.
The grip itself matters enormously. Activities requiring sustained, forceful gripping - like using a screwdriver, carrying shopping bags by the handles, or squeezing a computer mouse - create eccentric loading on the extensor carpi radialis brevis tendon. This tendon has to work overtime to stabilize your wrist while you grip, especially when the load is held away from your body with your elbow extended.
Repetitive activities compound the problem. Whether it's painting, using hand tools, or even playing tennis with poor technique, the constant contraction and relaxation of these small forearm muscles creates microtrauma faster than the tissue can repair. Computer work is a massive contributor - hours of mouse clicking and typing with poor wrist positioning creates the perfect recipe for overload. Even the way you lift objects matters: lifting with your palm down (pronated) and elbow straight places much higher demands on these tendons than lifting with your palm up and elbow bent.