Muscle of the week: Psoas
This week's muscle is the PSOAS. It is a long muscle, about as long as your biceps, and it runs from the side of the spine to the front of the hips. It is right in front of the kidney, and runs behind and under your pelvic organs.
Its main job is to flex the hip. In a pinch it will contract to protect the spine, but when this happens you can get a lot of back pain because your back joints and discs are jammed. How to fix back pain when the psoas contracts to protect the spine? Strengthen the transverse abdominus to contract first, that way the psoas goes back to being a hip flexor instead of a back protector (http://comstockpt.com/2012/02/01/806physicaltherapyolympia/)