Most people have never heard of the psoas muscles, yet problems with these muscles play a frequent role in hip, groin, and low back pain. There are two psoas muscles, one on each side of the body. They are long, thick, ropey muscles that originate deep in the abdomen at the lumbar vertebrae, run into the pelvis where they join another muscle called the iliacus, before attaching to the femur, or thigh bone.
These muscles allow us to flex the hips and lift our thighs upward toward the torso. They assist us in climbing stairs, walk uphill, run, etc. They also help stabilize the spine. If these muscles become too tight, shortened, which can occur from overuse, or prolonged sitting, they pull on the small of the back forward. This causes overdue stress on the lumbar vertebra, which then can lead to (along with other factors) low back pain, groin pain, sciatica, hip pain, and can contribute to arthritis in the lumbar spine over time.
Acupuncture is very beneficial for all of the above mentioned pain syndromes. However it is extremely important to strengthen and stretch these muscles, as well as the rest of the core muscles and hip flexors, to maintain proper use and balance, and less pain!
Check out this site about strengthening and stretching the psoas muscles.
"How to Stretch and Strengthen the Psoas"