An Electromyographic Assessment of the “Bear Hug”: An Examination for the Evaluation of the Subscapularis Muscle

Purpose The lift-off and belly-press tests are common tests for evaluation of the subscapularis. We compared these tests with the recently developed bear-hug test by assessing electromyographic (EMG) activity of the shoulder internal rotators during examination. Methods Twenty-one healthy male volunteers (mean age, 22.95 ± 3.71 years; mean weight, 73.48 ± 6.93 kg; mean height, 68.76 ± 2.26 cm) with no previous history of shoulder surgery or injury participated in the study. Fine-wire and surface EMG activity of the glenohumeral joint internal rotators (i.e., upper and lower subscapularis, pectoralis major, and latissimus dorsi) was recorded while 5 subscapularis tests were being performed (bear hug at 0°, 45°, and 90°; lift off; and belly press). Peak EMG values were normalized to the maximum voluntary isometric contraction (MVIC) for each muscle. A 4 (muscle) × 5 (test) analysis of variance with repeated measures on test was used to analyze peak EMG activity (percentage of maximum voluntary isometric contraction). Follow-up univariate analysis of variance and Tukey post hoc analyses were performed for each of the 5 tests. Results The bear-hug test performed at 45° of shoulder flexion showed significantly greater peak EMG activity in the upper subscapularis (107.64% ± 63.52%) and lower subscapularis (85.75% ± 64.69%) compared with the pectoralis major (41.43% ± 25.42%) and latissimus dorsi (20.32% ± 15.70%) (P < .05). The bear-hug test performed at 90° of shoulder flexion showed significantly greater peak EMG activity in the lower subscapularis (166.0% ± 132.71%) compared with the upper subscapularis (97.23% ± 70.78%), pectoralis major (50.63% ± 29.60%), and latissimus dorsi (17.56% ± 13.64%) (P < .05). The belly-press test showed significantly greater peak EMG activity in the upper subscapularis (77.88% ± 53.23%) and lower subscapularis (71.82% ± 46.49%) compared with the pectoralis major (18.49% ± 14.85%) and latissimus dorsi (34.85% ± 27.73%) (P < .05). Conclusions The bear-hug examination performed at 45° of shoulder flexion and the belly-press test may be valuable diagnostic tools in the clinical evaluation of the upper subscapularis muscle. In addition, the bear-hug test at 90° of shoulder flexion may be a valuable diagnostic tool in assessing the clinical function of the lower subscapularis. Clinical Relevance The bear-hug examination performed at specific degrees of shoulder flexion may be a valuable way to assess the function of the subscapularis muscle. The lift-off and belly-press tests are common tests for evaluation of the subscapularis. We compared these tests with the recently developed bear-hug test by assessing electromyographic (EMG) activity of the shoulder internal rotators during examination. Twenty-one healthy male volunteers (mean age, 22.95 ± 3.71 years; mean weight, 73.48 ± 6.93 kg; mean height, 68.76 ± 2.26 cm) with no previous history of shoulder surgery or injury participated in the study. Fine-wire and surface EMG activity of the glenohumeral joint internal rotators (i.e., upper and lower subscapularis, pectoralis major, and latissimus dorsi) was recorded while 5 subscapularis tests were being performed (bear hug at 0°, 45°, and 90°; lift off; and belly press). Peak EMG values were normalized to the maximum voluntary isometric contraction (MVIC) for each muscle. A 4 (muscle) × 5 (test) analysis of variance with repeated measures on test was used to analyze peak EMG activity (percentage of maximum voluntary isometric contraction). Follow-up univariate analysis of variance and Tukey post hoc analyses were performed for each of the 5 tests. The bear-hug test performed at 45° of shoulder flexion showed significantly greater peak EMG activity in the upper subscapularis (107.64% ± 63.52%) and lower subscapularis (85.75% ± 64.69%) compared with the pectoralis major (41.43% ± 25.42%) and latissimus dorsi (20.32% ± 15.70%) (P < .05). The bear-hug test performed at 90° of shoulder flexion showed significantly greater peak EMG activity in the lower subscapularis (166.0% ± 132.71%) compared with the upper subscapularis (97.23% ± 70.78%), pectoralis major (50.63% ± 29.60%), and latissimus dorsi (17.56% ± 13.64%) (P < .05). The belly-press test showed significantly greater peak EMG activity in the upper subscapularis (77.88% ± 53.23%) and lower subscapularis (71.82% ± 46.49%) compared with the pectoralis major (18.49% ± 14.85%) and latissimus dorsi (34.85% ± 27.73%) (P < .05). The bear-hug examination performed at 45° of shoulder flexion and the belly-press test may be valuable diagnostic tools in the clinical evaluation of the upper subscapularis muscle. In addition, the bear-hug test at 90° of shoulder flexion may be a valuable diagnostic tool in assessing the clinical function of the lower subscapularis.