The psoas muscle connects the lower middle spine to the top of the leg, making it one of the most important muscles in your body. You may not give this muscle much thought, as it’s deeply embedded within your body; but when it’s tight or injured, you experience a range of discomforts and injuries, including low back pain, sciatica, disc problems, hip degeneration, knee pain and pelvic pain.
A tight psoas can also compromise the range of motion you have in your low back, shoulders and hips. Stretching this hip flexor muscle is simple and necessary if you participate in activities that regularly shorten it, such as sitting for long periods or sports including running and cycling.
Running, walking and sitting all engage the psoas muscle. When you raise your knee, the psoas contracts. When the leg swings back, as during a running stride, it lengthens the muscle. Sitting for hours at a time leaves the psoas in a contracted position — habituating it into tightness. When it’s tight, you suffer posturally from an arched lower back, anterior pelvic tilt and hunched-forward shoulders. These postural abnormalities can lead to compression of the lumbar discs of the spine.
A way to determine if a psoas muscle is extremely tight is to lie on the floor with both legs extended in front of you. Hug one knee into the chest and, if the other leg lifts off the floor, chances are that the psoas of the extended leg is overly tight. Try this on both sides, as one side may be tighter than the other.
Stretch after doing this analysis. While on the floor, bring both legs to a 90-degree angle; ensure your tailbone stays on the floor. Draw the extended right leg toward your chest using your hands and place the left foot on the floor, knee bent. Slowly inch your foot along the floor, extending the left leg, to stretch the psoas. Go just to the point of mild sensation — not pain. Hold for 20 seconds or longer and repeat on the other side