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All Things Hip Flexion

Hip Flexors are important for many reasons but two I want to focus in on are how they:

  1. Control position of the pelvis

  2. Control position of the femur

Limitations or dysfunction with hip flexion AND muscles that produce hip flexion can lead

  • Hip Pinching

  • Snapping Hip

  • Iliopsoas Bursitis

  • Iliopsoas Tendinopathy

  • Nonspecific Anterior Hip Pain

  • Bony Morphologies such as CAM and PINCER lesions within the hip (head of femur and socket of pelvis)

  • Acetabular Impingement

I’m sure you have heard: “Sitting causes hip flexor tightness.” or “My psoas is knotted up.” Or some variation of that. You’ve tried standing more. You’ve tried aggressive stretching to your anterior hip. You’ve smashed, released, rolled, and got pso-rite; but the tightness still lingers. I wonder why?Let’s break it down.

Hip flexion is a movement that occurs through combined actions of different muscles; seven if you’re counting.

  1. Iliacus

  2. Psoas

  3. Tensor Fascia Latae (TFL)

  4. Rectus Femoris

  5. Sartorius

  6. Adductor Brevis

  7. Pectineus

Muscles can produce and play a role in primary movements, secondary movements, and even tertiary movements. For example, the rectus femoris is part of the quadriceps muscle group whose role is to produce knee extension (primary), control knee flexion forces (primary), and hip flexion (secondary).

But who ALWAYS takes the blame for hip flexor tightness and dysfunction: the psoas. And this is why I think it is important to address Psoas first.

Lumbo-pelvic disassociation is a term you hear often in the athletic training and human movement communities. The ability to move the trunk on a stable lower body or the ability to move the lower body on a stable pelvis. For optimal performance and pain management it’s vital to be able to move those two regions independently of the other. Being able to recruit and control the right muscles and patterns for each depends on hip flexors being able do what they are supposed to do. Since the Psoas muscle has primary actions for femur, pelvis, and lumbar spine; it’s a good place to start if limitations exist.

The Psoas muscle is deep. It’s also very long as it originates in the upper lumbar spine, crosses your pelvis, and then attaches onto the femur. It plays an important role with the iliacus in hip flexion motion, anterior tilting your pelvis, and extending your lumbar spine; forming the muscle Iliopsoas.

It’s near impossible to palpate and positively effect the Psoas muscle with just forces from our hands and other mobility tools.  We have to press through skin, fascia, layers of abdominal muscles, and abdominal viscera. You may be able to put pressure on the muscle belly BUT its likely you have no idea what you are truly mobilizing or feeling.

The dark red areas illustrate the Psoas muscle. The top of the picture is anterior. So you can appreciate how deep the muscle really is.

Here you can see the major muscles involved in hip flexion movement.

You can also appreciate the origin of the Psoas very high in the lumbar spine and follow it down to its insertion on the femur as it meets the Iliacus muscle.


There is a quick and easy test we can use called the Thomas Test to help guide and assess our hip flexor mobility with an objective measure.

Begin by sitting on the edge of a table. Lay back as you bring both knees to your chest. Allow one leg to freely lower to the ground as you keep the opposite leg pulled to your chest. Be sure to keep your lower back flat and do not allow yourself to arch your back and flare your ribcage.

Ideally the lowered leg will be able reach full extension (parallel to the floor or table) AND you will be able to bend the knee to 90 degrees. If you pass this test BUT still feel flexor tightness then true shortening is the not the reason for your tightness.

You can have tight muscles that are not tight due to shortness (requiring elongation and stretching) but rather tight because the central nervous system is creating necessary tension in that muscle group for protection and stability.

By strengthening the hip flexor muscle group through various ranges of hip flexion you can reduce the feeling and perception of tightness in those cranky and stubborn hip flexors.

Most of our exercise selections will incorporate both the controlled movement through a degree of hip flexion AND controlled core stability. If we can create more motor control and true stability through our core that can free up our iliopsoas to work as the primary mover of hip flexion as opposed to overworking its role in creating core stability.


Phase 1: Keep your lower back flat and in contact with the ground. Brace your core and feel yourself pull from the anterior hip as you bring your knee towards the chest. If you feel abnormal pain or pinching trying moving your thigh into more abduction (away from your body) as you turn the foot more inward. This is a scour test we often use to find the most optimal position for squat depth.

Phase 2: This will change the hip flexors isometrically. Again, be sure to keep your lower back flat against the ground. As you drive the opposite leg into extension. If reaching full knee extension is challenging try keep the knees slightly bent and tap the heel down. This shortens the lever arm for the hip flexors to work through making it less difficult.

Phase 3: This position addresses more active hip extension by working from the bridged position. You may find this position less challenging on your hip flexors given the degree of knee bend. No worries, we got you covered in Phase 4.

Phase 4: The most important thing to control in this progression is hip extension. You will notice that as you begin pulling your knee towards your chest, the stance leg is going to want to drop towards the ground. Keep your posterior chain engaged (spinal stabilizers, glutes, hamstrings) to allow your hips a more stable pelvis to work on.

Frequency: 2 sets of 10-12 on each leg.


This 1/2 kneeling variation is a good place to start because you don’t have to account for as much positioning demand. The goal is to keep your trunk vertical (do not lean backward) as you lift the knee upward and hold for 2-3 seconds. I am using a bumper plate. The taller the object the foot is placed on the further you will move to end range making it much more challenging to lift off.

The full standing position is brutal. Be sure to knee the hips stacked over top of your knee and ankle and do not allow the knee to bend (I struggled in the video). Keep the stance glute squeezed and do not lean backwards. Adding in the knee extension makes the lever arm for the hip flexor even greater equaling more stress applied. Use an appropriate box height for your hip flexion mobility and leg length.

Frequency: 2 sets of 10-12


Going back to the introduction of this topic, we mentioned how 7 different muscles contribute to hip flexion movement. Some of those movements also adduct (add to the body), externally rotate, and internally rotate the hip. This position allows use to work through hip flexion through different angles like a clock. The goal is slow and controlled. By pulling our opposite knee to chest we prevent any excessive lumbar spine compensation.

Frequency: 2 sets of 12


Rectus Femoris crosses both the hip AND knee joint. It’s a forgotten muscle of the hip flexion group so this one is great to challenge the ability of that muscle to stabilize the hip in flexion and work on the knee with resisted knee extension. We also get to address hamstring extensibility and control.

Frequency: 2 sets of 8-12

Stability and mobility drills are only effective if we create the desired changes we are looking for. Always test and re-test movements to see if things seem less “tight”, “stiff”, and more natural. Sitting in the bottom of a squat is always a good place to start.

By addressing hip flexion the correct way we can restore proper length-tension relationships to all muscles that cross and act on the lumbopelvic complex resulting in:

  • pain reduction

  • improved mobility and stability

  • more force production

  • decreased injury risk

  • more PR’s

Better prepared for your next move!

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Dr. Bryan Keith

Myomuv PT

We help active adults and athletes return to the activities they love without pain, without taking time off, and feeling more confident and capable than ever before.