Some thoughts on hip flexion strength and knee pain

Posted on June 22, 2018

(Last Updated On: June 22, 2018)

Mike Reinold ran a post about the importance of hip flexion strength when it comes to knee pain. He mentions hip flexion strength is often lacking in people with patellofemoral pain (knee cap pain) issues and how to assess hip flexion strength. I want to expound on this and talk about how to strengthen the hip flexors if they are weak, and how to get out of as much knee pain as you can until the hip strength catches up.

1) Strengthening hip flexion (long-term fix)

It’s important to note the method used to test hip flexion strength in the other article is testing the strength of the psoas and not all the hip flexors. Because the test is done with the knee above 90 degrees the psoas is the only still active hip flexor, therefore being the only hip flexor tested.

-> The psoas is the only hip flexor which connects above the hip. Because the other hip flexors start at the hip, then go lower, they can’t pull the knee above the hip.

Although not talked about in the article, this is done because RARELY are any other hip flexors weak.  The hip flexors bringing the knee to 90 degrees are often too strong relative to the psoas, causing an imbalance in strength between the various hip flexors. This is important when deciding what exercise(s) to use to strengthen hip flexion. We want to pick exercises where the knee is always above 90 degrees to make sure we selectively strengthen the psoas and not the other, already strong, hip flexors.

-> This is all very common in those with hip pain as well.

Here’s one exercise for strengthening the psoas:


Make sure you or your client does not lean back to try to accomplish the hip flexion. It’s subtle, but you can see the demonstrator actually arching the lower back despite trying to show proper form in the above video. Because this will often happen, and can be very hard for the person to recognize, I prefer to put the person against a wall:


This forces the person to stay tall and helps them recognize when they are arching their lower back, since they will feel when it comes off the wall.  Just make sure you don’t tilt yourself to a side compensating for a lack of hip flexion. Try doing the exercise in front of a mirror if you’re not sure whether you are side tilting.


2) Short-term fix for the knee pain

Simple: do this exercise every hour, or as needed, and you’ll likely notice relief in your knee pain.


This works because people who need hip flexion strength often walk with their knees hyperextended:

knee pain causes

Chronically hyperextended knees are a sign the quadriceps are working overtime, specifically the rectus femoris. The rectus femoris is one of those overactive hip flexors, which has become too strong compensating for the weak psoas.

Inferior patellar glides help loosen the rectus femoris and other quadriceps, and give some relief of that knee pain. Especially when that pain is most present on the knee cap.

Remember though, this is not meant to be a long-term fix, that’s what the psoas work is for. (And practicing “stand with a little give in the knees” / “unlock your knees.”) But it’s nice to not be in as much pain til that psoas can catch up strength wise.

Give it a shot.


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Posted in: Hip Pain, Knee Pain, Pain