Question: I was just reading through “The role of shoulder muscles is task-specific” by Boettcher et. al (2010, Journal of science and medicine in sport) which found that in 90 degrees of shoulder abduction: – trapezius and serratus EMG activation increased with isometric external rotation – trapezius and serratus activation dropped to nearly zero with isometric internal rotation at 90 degrees shoulder abduction Could you perhaps speak to how or why the body creates compression of the thorax in what would otherwise be an expansive movement (shoulder ER) and seems to allow expansion of the thorax in what would be a compressive movement (shoulder IR)?
In this video: I explain how this finding is actually consistent with The Model in regard to inhalation and exhalation strategies via overcoming and yielding muscle actions of the scapular and rotator cuff muscles.
#rotatorcuffexercises #trapezius #billhartmanpt
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