Stretching the posterior shoulder is a major factor in a multitude of shoulder rehab programs �. There are many ways to stretch the posterior shoulder, one of which we highlighted a few weeks ago. Two other alternatives are shown here in the video: the sidelying sleeper stretch and the sidelying horizontal abduction stretch. . A previous study had shown that the horizontal abduction stretch was more beneficial in restoring internal rotation at the shoulder than the sleeper stretch. ‼️However a newer study by Yamauchi et al 2016 found that BOTH stretches effectively increased shoulder internal rotation and horizontal abduction with no significant differences between groups.‼️ . The cool thing about this study though, is that they looked at muscle stiffness of both the infraspinatus and teres minor using ultrasound. Both of these muscles make up what is known as the "posterior cuff." It is the posterior cuff, in addition to the posterior shoulder capsule, which contributes to posterior shoulder tightness. . ➡️Interestingly enough, the study found that the sleeper stretch decreased infraspinatus muscle stiffness. ➡️Whereas the sidelying horizontal abduction stretch decreased teres minor stiffness. . Why is this relevant? For baseball pitches, the teres minor demonstrates the highest level of EMG activity of all the shoulder muscles during the deceleration phase. Furthermore, at 90 deg of abduction (ie the position of the shoulder during throwing), the teres minor to infraspinatus muscle activity ratio is significantly higher than a 0 deg of abduction. Thus, the throwing motion requires higher intensity eccentric contraction of the teres minor than the infraspinatus, which could lead to the teres minor being more fatigued and thus more muscle stiffness after pitching. . ✅MORAL OF THE STORY: If you're a baseball player, try the sidelying horizontal abduction instead of the sleeper stretch to stretch your posterior shoulder!
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