Isolated glenohumeral range of motion, excluding side-to-side difference in humeral retroversion, in asymptomatic high-school baseball players

Abstract

Cross-sectional study, Level III.

Posterior shoulder tightness can be a risk factor of scapular malposition: a cadaveric biomechanical study

“…In evaluating throwing athletes with pathologic internal impingement of the shoulder, Myers et al 16 found that the glenohumeral internal rotation deficit was 19.7 . Mihata et al 14 reported that the decrease in maximum shoulder internal rotation was 12.7 in the asymptomatic throwing shoulder. Therefore, our posterior tightness model was similar to that in the throwing shoulder.…”

“…Throwing athletes commonly have posterior tightness in the throwing shoulder. 1,4,14 This posterior shoulder tightness results from posterior capsular contracture 4,16,18 or tightness of the infraspinatus and teres minor muscles due to repetitive throwing motion. 9 Severe posterior shoulder tightness is thought to cause subacromial impingement, 3,7,19 pathologic internal impingement, 12,16 and superior labral anterior and posterior lesions.…”

Reliability and Validity of a 1-Person Technique to Measure Humeral Torsion Using Ultrasound

“…More importantly, many investigators 2,10,11,19,20 did not normalize ROM measurements based on HT despite the known influence it has on ROM measures. 5,7,[21][22][23][24][25][26][27][28][29] As such, clinicians should be cautious when interpreting these studies and blindly implementing interventions to ''improve'' rotational deficits based on simple bilateral goniometric assessments. Incorporating HT measurements into ROM calculations as noted by others 5,6,25,32 will enable clinicians to accurately determine how much and in which direction interventions should be implemented to address deficits caused by soft tissue.…”

“…Incorporating HT measurements into ROM calculations as noted by others 5,6,25,32 will enable clinicians to accurately determine how much and in which direction interventions should be implemented to address deficits caused by soft tissue. Whereas implementing HT measurements has not become part of routine clinical practice, several authors 7,23,25,31 have suggested its implementation to accurately differentiate between bony and soft tissue adaptations that may affect rotation ROM measures in overhead athletes. The results of this implementation may be to prevent any deleterious effects that could result from stretching the glenohumeral joint beyond its physiological end ROM.…”

“…2,6,10 Interestingly, these adaptations, which may result in deficits in either internal or external rotation (or both), have been identified as risk factors for upper extremity injury. 2,10,11,19,20 Investigators 5,7,[21][22][23][24][25][26][27][28][29] have demonstrated that osseous adaptions may account for a larger part of the adaptations observed in internal-rotation deficits and external-rotation gains in the overhead-throwing shoulder. In fact, research-ers 5,30,31 have reported that decreases in humeral torsion (HT) accounted for internal-rotation deficits of the glenohumeral joint.…”