Download or read book Anatomical and Neuromuscular Adaptations in Division I Collegiate Baseball Players written by Stephen J. Thomas and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, it has been shown that the shoulder is the most commonly injured joint in both high school and college baseball accounting for 17.6% and 10% of all baseball injuries that are reported, respectively. It has been theorized that these injuries may be due a cascade of deleterious anatomic and biomechanical adaptations that occur from the continuous stress of overhead throwing. The purpose of this work was to examine potential adaptations to specific anatomic structures that may contribute to alterations in biomechanical variables, increasing the risk for shoulder injuries. This was addressed in four studies. The first study used a novel ultrasound method to determine if the posterior capsule adaptively thickened in baseball players due to the chronic stress placed on the dominant shoulder during the deceleration phase of throwing and if the thickness is associated with alterations in glenohumeral and scapular motion. The results suggest that the dominant arm does develop an adaptive thickening in the posterior capsule, most likely due to the chronic deceleration stresses of throwing, and this thickness is associated with the common clinical observations including loss of glenohumeral internal rotation and increased scapular upward rotation. The second study sought to determine if humeral retroversion was increased on the dominant arm and if relationships existed between glenohumeral range of motion and posterior capsule thickness. The results demonstrated that the osseous adaptation of increased humeral retroversion is present in healthy collegiate baseball players and is correlated with glenohumeral range of motion and posterior capsule thickness. The third study attempted to determine if bilateral alterations existed in subacromial space and if these alterations are associated with changes in scapular upward rotation. The results suggested that differences in subacromial space did not exist in this asymptomatic cohort and that subacromial space was not related to scapular upward rotation. The fourth study attempted to determine if alterations in neuromuscular control and stiffness regulation occurred on the dominant arm and if relationships existed between posterior capsule thickness and joint stiffness. The results demonstrated that there was increased serratus anterior preparatory EMG area and decreased co-contraction in both the preparatory and reactive phases. Both total joint stiffness and short range stiffness were increased on the dominant arm and a direct correlation was revealed with posterior capsule thickness. From these studies we have drawn three overall conclusions: (1) healthy collegiate baseball players develop both soft tissue and bony adaptations in the dominant arm, which are most likely due to the chronic stress of overhead throwing, (2) these anatomic adaptations are associated with changes in glenohumeral and scapular range of motion that are commonly seen in both healthy and injured overhead athletes and (3) healthy collegiate baseball players have changes in neuromuscular control and stiffness regulation on the dominant arm that are clearly an acquired adaptation needed to efficiently absorb large amounts of energy created during throwing. Morphologic changes of the posterior capsule were shown to correlate with joint stiffness suggesting that joint stiffness can also be enhanced by static restraints. Overall, this information will provide researchers and clinicians with normative data on the anatomic and neuromuscular adaptations associated with healthy baseball players and can be used for comparisons with injured athletes.