EMG of Elbow Function in Tennis Players with Lateral Epicondylitis
Abstract & Commentary
Synopsis: Abnormal mechanics were isolated in the wrist and elbow during the single-handed backhand tennis stroke. These abnormalities were thought to lead to increased stress in the wrist extensors that could lead to repetitive injury at the lateral epicondyle.
Source: Kelly JD, et al. Am J Sports Med 1994;22(3): 359-363.
Kelly and colleagues did an extensive analysis of electromyographic (EMG) changes in five separate muscles about the wrist and elbow during the single-handed backhand tennis stroke. They used fine wire electrodes in five separate muscles and then recorded the backhand stroke on high-speed film and synchronized it with the EMG signal. Two groups of volunteer patients used were (a) those who had never experienced tennis elbow in the past, and (b) those who had experienced tennis elbow in the past but were in the subacute phase and, therefore, had minimal symptoms. Kelly et al found that the injured players had greater activity in their wrist extensors and pronator teres muscle during ball impact and early follow-through. Kelly et al thought this might have been caused by abnormal mechanics, and they were able to document these on film. Abnormalities included a "leading elbow," wrist extension, open racket face at the time of impact, and ball impact on the lower half of the strings. Kelly et al believed that the abnormalities they isolated would not only lead to a poor level of play but also to increased stress in the wrist extensors and the pronator teres that could lead to repetitive injury at the lateral epicondyle.
Comment by James P. Tasto, MD
Lateral epicondylitis is a frequently encountered injury in sports medicine. Not only do we see this in a high percentage of tennis players, but also in golfers, industrial workers, people who carry a great deal of baggage, and, often, people who do normal household activities and gardening. Conservative treatment is usually sufficient to overcome most symptoms. Treatment includes concentric and eccentric exercises, counterforce bracing, nonsteroidal anti-inflammatories, and judicious use of corticosteroidal injections. Surgical procedures vary considerably but are generally focused around releasing and reattaching the extensor carpi radialis brevis, removal of inflammatory tissue, and, on occasion, creating an osseous bed for increased vascularity and better reattachment of the extensor mechanism. This article points out the importance of isolating the cause of all tennis elbow complaints. We are familiar with many of the entities that contribute to lateral epicondylitis in the tennis population, such as those mentioned above, as well as racket handle size, string tension, and racket head size. These should all be looked at carefully by the athlete. It is important to isolate etiology for all of your patients whether they are tennis players or golfers. Have them work specifically on appropriate mechanics, avoid provocative situations that give rise to this inflammatory condition, and choose proper equipment.
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