ELECTROMYOGRAPHIC AND NERVE BLOCK ANALYSIS OF THE SUBSCAPULARIS LIFTOFF TEST

The inability to perform the ''liftoff'' test has been attributed to a subscapularis muscle or tendon injury. The goals of this study were t o evaluate the activity of the glenohumeral muscles during performance of the ''liftoff'' maneuver and to identify the most effective initia l upper extremity placement that isolates the subscapularis musculoten dinous unit. In the first phase of this study 15 subjects accomplished four proposed versions to the ''liftoff'' test while their intramuscu lar electromyographic activity in select glenohumeral muscles was reco rded. The second phase of this study assessed the ability of five subj ects with a nonfunctional subscapularis musculotendinous unit to perfo rm the same proposed versions. On the basis of electromyographic data none of the proposed versions to the ''liftoff'' maneuver isolated the upper and lower subscapularis muscle from either the teres major, lat issimus dorsi, posterior deltoid, or rhomboid muscles (p > 0.05). In t he presence of a nonfunctional subscapularis musculotendinous unit, th e subjects were able to perform all of the proposed versions to the '' liftoff'' maneuver except one: elevation of the dorsum of the hand fro m the posterior-inferior border of the scapula (maximum internal rotat ion test). Although significant electromyographic activity was generat ed in the potentially confounding shoulder girdle muscles during the m aximum internal rotation ''liftoff'' test, a successful test appears t o be dependent on the isolated glenohumeral internal rotation function of the subscapularis muscle.