THE RELATIONSHIP BETWEEN THE HUMERAL RETROVERSION ANGLE AND THE ACTIVE SHOULDER ROTATION IN VOLLEYBALL PLAYERS

Abstract

The humeral retroversion angle (HRA) is the acute angle between the proximal and distal articular surfaces of the humerus, in a medial and posterior direction. An increased HRA was suggested as one of the osseous adaptation seen in the dominant shoulder of overhead athletes with functional implications on the range of shoulder external rotation. Based on literature we could expect a higher HRA on volleyball players comparatively with the non-athletes. Almost all known studies describe side-to-side difference, however a lack of information exists about relationship between HRA and the active range of shoulder external rotation on volleyball players. Thus, the purpose was to compare a group of volleyball players with a group of non-athletes regarding humeral osseous adaptation, measured by the HRA, and the range of active shoulder external rotation.