The effect of isometric shoulder internal and external rotation on the acromiohumeral distance.

Objective: This study aimed to determine the effect of isometric internal and external rotation at various degrees of shoulder abduction on the acromiohumeral distance (AHD).

Design: This was a prospective study that used a within-subject repeated-measures design and randomization of independent variables. Data from 29 of 58 (40 women, 18 men) prospectively enrolled healthy subjects were used for analysis.