The effect of long and short head biceps loading on glenohumeral joint rotational range of motion and humeral head position

Purpose To evaluate the effect of loading the long and short heads of the biceps on glenohumeral range of motion and humeral head position. Methods Eight cadaveric shoulders were tested in 60° abduction in the scapula and coronal plane. Muscle loading was applied based on cross-sectional area ratios. The short and long head of the biceps were loaded individually followed by combined loading. Range of motion was measured with 2.2 Nm torque, and the humeral head apex position was measured using a MicroScribe. A paired t test with Bonferroni correction was used for statistics. Results Long head loading decreased internal rotation in both the scapular (17.9 %) and coronal planes (5.7 %) and external rotation in the scapular plane (2.6 %) ( P