Tight hip flexors can be the bane of desk sitters, deep squatters, avid walkers etc. I’m going to take you through the why and the how (to fix).
The Why
This is a simple diagram of your hip flexors. They’re all active when acting at the hip from an extended position, but the more proximal flexors may be more active when the hip is past 90° of flexion, and the more distal flexors (like rectus femurs) has more elastic potential when the knee is in flexion.
Tight hip flexors may be coupled with an inability to internally rotate and extend the hip. This is because these movements are coupled with poor hip capsule (or joint) extensibility into extension. Natural hip extension experienced whilst walking or deadlifting or running etc. would naturally train the hip flexors in an elongated state. The absence of this available movement leads to tightness.
As well as this, poor hip capsule extensibility may also be common in those who habitually don’t use hip extension (such as desk sitters) which will cause a shortening of the hip flexors.
Our goal is to elongate the hip flexors and incorporate hip extension into more commonly used movement patters (i.e. motor systems)
How
Below are my most commonly used methods of doing this, ranging from beginner (or non athletic) to advanced (more athletic)
Hip flexor stretch: Basic
This is a very easy hip flexor stretch here. I find it really effective to instruct the patient to push forward on the knee using their hip extensors (i.e. glutes) for more movement pattern integration. Kelly Starett can be seen incorporating bands into this stretch here to apparently create a distraction on the hip to prevent impingement (that we may commonly experience on deep hip flexion). It must be noted however that the hip is the strongest joint in the body. Could attaching a band to a stretch really cause much distraction at all, or is it another mechanism of action? Turn the back foot out to also improve internal rotation.
Hip flexor stretch: Advanced
This is a more advanced exercise eccentrically load the hip flexors, see here. This is actually being performed rather poorly. He shows poor control and doesn’t actually achieve any hip extension BUT you can get the idea of what he’s trying to achieve. I actually prefer an exercise where I ask a patient/ client to lay on a bench with a kettle bell on their foot, and slow take the hip past extension to load the hip flexors eccentrically, neurologically grooving their function whilst the hip is in extension and the abdominal muscles are braced.
Training hip extension: Basic & Advanced
The unloaded glute bridge is a great way to do this. You must focus on instructing the patient/ client to push until their hips are above their knees. Remember, extension is what we’re looking for here. See the exercise performed here. You will then see Bret Contreras (aka the Glute Guy) move onto the more advanced exercise performed  with the barbell for you enthusiasts out there (also a great exercise to develop a firmer behind :D)
Let us know how you get on! And post below for any questions to be answered