The psoas major ( aka hip flexor) has an active role in hip flexion but also plays a more important role in vertebral stabilization ( keeping the vertebrae from rotating in the frontal plane) than in generating leg motions. The psoas attaches at many locations, passes over multiple joints and entraps a major neurological network, which explains why so many injuries can be attributed to one misbehaving muscle. These many attachments make it extremely important that the psoas can lengthen enough to allow the spine, pelvis and hips to articulate and move naturally for a pain-free and injury-free body.
Sitting for hours on end ( desk, driving in car, etc..) tightens the psoas affecting our ability to walk upright, by inhibiting the psoas’s ability to fully lengthen and thus allowing for the hips to extend. Moving from this tight psoas position and moving right to any activity or exercise it’s no wonder why we are seeing so many injuries to the low back, pelvis and hips. In other words prolonged periods of hip flexion ( sitting ) lead to injuries. The key is to get the body into hip extension and reinforce those proper body mechanics.
Try to reduce time in hip flexion by:
1. Using standing workstations instead of desk sitting.
2. Reduce treadmill and bicycle workouts and weight machines and increase outdoor walking /running, in-line skating and body movements that encourage more extension such yoga exercises ( warrior or lunge poses).
3. Pay attention to rib-thrust. Rib-thrusting during these exercises reduces their effectiveness in lengthening the psoas. Cue: lower the bottom ribs until they line up over the pelvis, to keep the muscular attachments in check.
4. Psoas stretching and hip/back extension exercises.
Psoas and the Treadmill:
The treadmill changes our natural gait pattern from hip extension to greater hip flexion, which leads to greater psoas tension. Our body needs to push back in order for it to go forward. Because the treadmill belt moves backwards, our feet meet little to no resistance when they push off. Hence, we lift our legs in front of us and then fall forward. Treadmill mechanics recruit and reinforce an already too-tight psoas.
Take away: Get outside and walk or run!!