Midline stabilization is essential for effective functional movement. Kelly Starrett, of San Francisco CrossFit, explains the essential anatomy and physiology of it in this excerpt from his one day seminar at CrossFit Santa Cruz on November 9, 2008.

The midline is the entire spine, and its stability is dependent not just on the core, but also on all the prime movers of the body, including the hip, glutes, and hamstrings. Excessive tightness in any of the prime movers will affect the core muscles, often resulting in low back pain.

In this part 9, Kelly works the quads, which are also a two joint muscle, and must be treated from both ends (knee and hip). Short quads are associated with both patella and hip issues. He shows a few tools to assess quads length, and how to do PNF for the quads.

This is the ninth of a series from Kelly on the theory and practice of stabilizing the midline in functional movement.

Watch this video in the CrossFit Journal here.