Psore in the Psoas?

By Katrina Hays via Trail Runner Magazine

Your hip flexors could be a limiting factor in your stride
"The psoas (SO-az) muscle originates in the front of your lumbar spine, dives down behind the kidneys, comes through the pelvis, meets up with the illiacus (which flexes and laterally rotates the thigh) and hooks onto a little bony protuberance on your femur called the lesser trochanter. The psoas major and psoas minor are commonly referred to collectively as hip flexors.

The psoas' primary action is to lift the thigh toward the body when the body is fixed, or pull the body toward the leg when the leg is fixed. Passing across the body's center of gravity, located at the top of the sacrum, the psoas is critical to regulating stability and balance.

"The psoas itself isn't really firing until the hip is flexed above 90 degrees," says Darcy Norman, PT, CSCS, Certified Athletic Trainer, and Director of Sports Performance at the Tahoe Center for Health and Sports in Truckee, California. Until that point, the quadriceps is doing most of the work. However, trail running over technical terrain requires a light, springy stride, which engages the psoas.

Test the strength of your psoas by standing straight and lifting one knee up until your thigh is higher than parallel with the floor. Without leaning backward, you should be able to hold the position for a few seconds without feeling tremendous strain or weakness in the psoas. If you cannot maintain this raised-leg position, your psoas is weak.

Check your psoas' flexibility while lying on your back with your legs extended straight. Bend one knee and pull it up towards your chest. The opposite extended leg should stay flat on the ground. If your thigh is pulled up off the floor at all, you have a tight psoas. Flexibility will probably differ on each side."