Here we have a shortening and a lengthening contraction. Yet the word ‘contraction’ means to shorten, so our language inhibits our understanding.
Injuries almost always occur on the lengthening contractions. A key to preventing injuries is to feel the counterbalance of the shortening contraction underneath the lengthening contraction.
The principles of shortening and lengthening contractions can be applied to any muscles.
Explore shortening and lengthening contractions of the thoracic and pelvic diaphragms with Bonnie in this short clip from her online course, Embodiment and Expression for Musicians and Singers.