The gluteus medius muscle is a primary stabilizer of the hip and when weak has been found to correlate with low back pain, hip pain, and knee pain. If you had to lose one muscle this would not be a good one to give up. I frequently find that the gluteus medius muscle is weak …
Great "Shoulder Pain" chart!
Psoas Muscle Release Exercise: "When the psoas is tight, the ability of the leg to extend (move back) at the hip is compromised during walking. This will create rotation at the pelvis which can lead to dysfunction of the back or pelvis. For the health of your spine and your whole body, the psoas muscles need to release and lengthen."
Athletico Physical therapy psoas stretch of the week