Q: The question that the student has is: “If the fascia is more ‘stretchable in a horizontal means, why are we working with the grain (AT – up the SFL)?
A: Let’s first distinguish between connective tissue structure and myofascia. Even though this image is brownish in Eric’s microscope, it is pure tendon – the strappy tendon of the latissimus near its insertion in the humerus, and obviously the tendon is running down to up in its orientation. There’s no muscle in this video.
The video shows that the tendon is easily stretched sideways, which makes sense, as in the body there would be very little sideways tension on the tendon so it would not build up cross-bridging to resist that force, because that force would not show up unless you were rubbing the distal end of your lat back and forth very vigorously on a fence post.