In an age when so many people in the U.S. spend the bulk of their days seated and/or sedentary, one of the more common muscle imbalance issues involves the hip flexors, says Seattle physical therapist Izette Swan.

And, while simply having tight hip flexors isn’t a major health problem in and of itself, Swan adds that the long-term effects of these muscles being tight can manifest in other, sometimes more-debilitating ways.

“If you have tight hip flexors, you’re of course setting yourself up for potential injury when exercising or otherwise being active,” said Swan, owner of Real Rehab Sports + Physical Therapy in Seattle. “But beyond that, perpetually tight hip flexors can, over time, lead to discomfort and pain in your back or your knees.”

What are the Hip Flexors?

A powerful link in your body’s kinetic chain, your hip flexors are the muscles that run from the front of either side of your lower spine to the fronts of your upper thighs, connecting your trunk through your pelvis to your thighs. They control hip flexion and protect against excessive hip extension.

When your hip flexors are tight, the length of the muscle group shortens. This can cause the muscles to continually pull forward on your spine, can tilt your pelvis forward and can limit your hip from extending back – a motion that is key to good mechanics during walking and running. This tightness can lead to strain, inflammation and pain in the low back.

“You might be surprised to learn that lower back pain is one of the most common ailments to come from tight and even weak hip flexors,” Swan said. “The shortening of the hip flexors is a common result of sitting for long periods of time, and unless an effort is made to exercise and stretch this muscle group, posture issues can develop, limiting your ability to walk and or run without pain in the low back, pelvis or hips.”

Tight hip flexors can also create an imbalance in the knees, which over time can also lead to pain, degenerative changes or a higher probability of injury.

So, how do you know if your hip flexors are too tight? Swan offers the following tests you can try on your own:

Supine Lying

While lying on your back with your legs flat and straight, does your back arch up off the floor? If so, this may be an indication that your hip flexors are too tight.

Thomas Test

Stand at the edge of a bed, grab one thigh and bring it toward your chest. Gently recline onto your back, letting the other leg hang free. If the back of the thigh does not rest at least level with the bed or below, your hip flexors maybe too tight.

If you suspect you might suffer from tight hip flexors, consider visiting a physical therapist, Swan says. Through an assessment, a physical therapist can pinpoint tightness, imbalances and weaknesses in your hip flexors as well as in your back and thighs that may put you at risk of pain or injury, then develop a plan for addressing and treating these issues.