Figures
Mechanical impingement ranges and potential structures. (A) Subacromial Impingement: Lower ranges of humerothoracic elevation (45°–60°). May impinge on the supraspinatus tendon, infraspinatus tendon, long head of the biceps tendon, and subacromial bursa. (B) Internal Impingement: Higher ranges of humerothoracic elevation (above 105°). May impinge on the supraspinatus tendon, infraspinatus tendon, labrum, and joint capsule.
Mean rotations at upper-range humerothoracic elevation: (A) Scapular anterior/posterior tilt, (B) scapular internal/external rotation, (C) scapular upward/downward rotation, (D) glenohumeral internal/external rotation. Green arrows point to favorable kinematic directions (increased scapular posterior tilt, external rotation, or upward rotation or glenohumeral external rotation). Red arrows point to potentially detrimental kinematic directions (scapular anterior tilt, internal rotation, or downward rotation or glenohumeral internal rotation).
Scapular and glenohumeral kinematics. Posterior view of right scapula and humerus. Potentially detrimental directions for scapular and glenohumeral kinematic rotations highlighted with the arrow. Figure 2 originally published in: Riek LM, Ludewig P, Nawoczenski DA. How “healthy” is circuit resistance training following paraplegia? Kinematic analysis associated with shoulder impingement risk. J Rehabil Res Dev. 2013;50:861–874.
Mean rotations at lower-range humerothoracic elevation: (A) Scapular anterior/posterior tilt, (B) scapular internal/external rotation, (C) scapular upward/downward rotation, (D) glenohumeral internal/external rotation. Green arrows point to favorable kinematic directions (increased scapular posterior tilt, external rotation, or upward rotation or glenohumeral external rotation). Red arrows point to potentially detrimental kinematic directions (scapular anterior tilt, internal rotation, or downward rotation or glenohumeral internal rotation).
Tables
Mean (Standard Deviation) Rotations at Upper and Lower Ranges of Humerothoracic Elevation and Mean Change (95% Confidence Interval) Between the Traditional and Modified Hand Positionsa
↵a ATPT (−/+)=scapular anterior/posterior tilt, where the negative sign indicates less anterior tilt, and the positive sign indicates more posterior tilt; IRER (+/−)=internal rotation/external rotation, where the positive sign indicates more internal rotation, and the negative sign indicates less external rotation; URDR (−/+)=upward rotation/downward rotation, where the negative sign indicates less upward rotation, and the positive sign indicates more downward rotation; and GHIRER (+/−)=glenohumeral internal rotation/external rotation, where the positive sign indicates more internal rotation, and the negative sign indicates less external rotation. Green font indicates modified position resulted in a favorable kinematic change. Red font indicates modified position resulted in a detrimental kinematic change. An asterisk (*) indicates a clinically meaningful change. When a significant interaction effect for exercise and hand position occurred, a dagger (†) indicates a pair-wise difference where the modified hand position resulted in improved kinematics over the traditional hand position.
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