Muscle strain on the radial wrist extensors during motion-simulating stretching exercises for lateral epicondylitis: A cadaveric study

The purpose of this study is to measure muscle strain on the extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) in cadavers and to identify effective stretching positions. In 12 frozen/thawed cadaveric arms, a strain gauge was attached to the ECRL and ECRB muscles, and increases in muscle strain were measured from a standard position (45° elbow flexion, neutral forearm, and neutral wrist) to 12 sequential arm and wrist positions. Muscle strain on the ECRL and ECRB with the elbow at 45° flexion was less than 10% regardless of forearm and wrist positions, whereas the majority of it was greater than 10% with the elbow extended. Maximal muscle strain on the ECRL and ECRB was obtained with elbow extension, forearm pronation, and wrist flexion–ulnar deviation, with mean values of 17.8% and 13.8%, respectively (greater than standard position, P < .05). Muscle stretching of the wrist extensors for lateral epicondylitis should be performed in this position.