Susan A. Matthews’ guided description of power stretching from the Lan Shou Quan system contains six steps to help the practitioner practice. I present step one in a previous post, which describes the beginning “basic mechanism of spiraling biomechanics and power stretching from the ground up through the legs to open/flatten the low back.” This is a basis for practically all movement in power stretching, if you want to transmit force from the ground through the upper body out to the hands. To reach this goal requires connecting the upper and lower body through the low back.
In Step 2, Shifu Matthews describes how to use the quadratus lumborum (which she describes in her video, Mind and Energy Movement in Taijiquan) to pull the lower rib cage securely down towards the iliac crest near the sacroiliac joint. “Do not arch the low back, rather open the low back by rooting (spiral screwing) into the ground with the feet (see Step #1). Release the front. Allow the shoulders and head to elevate by opening at the hips in the front. Also use the latissmus dorsi to stabilize the low back. The latissmus dorsi attaches to the humerus in the armpit. Contracting it should pull the shoulder and elbow down. Try one side, then the other, then both together. Try one side, feel the ribs contract in the back, feel the ribs open opposite front. We like rib action without twisting.”
On her website, Shifu Matthews includes instructions on testing with a partner how this step, along with step 1, can be applied.