What FAI is, What it’s Not and How That Affects its Management (Part I)

The body of research on FAI (hip impingement) has increased substantially over the past few years. The number of runners and triathletes treated with this diagnosis seems to be growing too. Most runners are told they have a misshaped bone in their hip that irritates the joint, causes a labral tear, or relates to another hip “issue.”
Let’s set some basics on what FAI is and what it is not.
Back in 2016, the Who’s Who of Hip Pain Managers (surgeons, researchers, therapists, etc.) got together to ” build an international, multidisciplinary consensus on the diagnosis and management of patients with FAI syndrome.” This was called the Warwick Agreement, which serves as an excellent template for understanding FAI and managing the condition.

Warwick Agreement.png

Here’s what they decided. In order to be diagnosed with FAI syndrome, you had to have…

  1. Positive imaging findings
  2. Motion related pain in the hip groin
  3. Positive clinical signs (pain with hip IR, FABERS, Scours testing, etc.)

You have to have pain with specific hip movements, positive clinical testing, and imaging that matches that. If you have just one or two of those, you do not have FAI Syndrome. 

Understanding those specific criteria is crucial. If someone’s hip anatomy is not “normal,” it does not mean there is a problem. There are many people with “abnormal” hip architecture that don’t have pain and can perform at extremely high levels of sport. Having hip anatomy different from “normal” does not guarantee you will have to have surgery. It is not something that is guaranteed to limit your performance. It is not something that guarantees you will get hurt in the future. 

If a runner is dealing with painful FAI, the assessments in the previous video will not feel great. Those assessments wouldn’t feel great on many people that DIDN’T have FAI. 

When the hip joint tissues are irritated, they generally don’t like those positions. The positions and movements aren’t inherently bad; the tissue is just upset. This has more to do with irritation than the word impingement. Impingement is NORMAL in the body. Tissues impinge upon each other all the time. When you take any joint to its end range of motion, bone, soft tissue, and other structures are going to push against each other. 

These impingement positions can get irritable, whether we run too much or recover too little. Load management is essential in all running-related injuries, whether dealing with tendinopathies, bone stress injuries, etc. Irritable hips are often more due to “too much too soon” than a runner’s specific bony anatomy. 

How does this relate to running? 

FAI often presents itself as “motion-related pain”. Many FAI patients can get through daily activities that don’t put their hip into greater hip ROM. When they have to sit, pick up their kids, or go up steps that they get pain.

Running is inherently a mid-range activity. That’s a good thing for a “ticked off hip”. The flexibility demands on the hip are very small compared to other sports. If we look at the work of Novachek, these are the ROM requirements for the hip and running. 


You may want a bit more wiggle room than the numbers listed above, but you don’t need that much hip mobility to run. 

Making assumptions

FAI is not a mobility or flexibility problem. Many times, runners dealing with hip pain will feel “tight.” Feeling “tightness” does not mean that more stretching or flexibility is needed. However, this is the route many people will go down. The standard treatment is aggressive manual work, stretching, and mobility drills that leave more hips feeling worse than better. Most of the patients I see will focus on managing tightness with end-range hip activities. There are many times when things feel tight that don’t need to be stretched. If you sprain your ankle and it swells up, it will probably feel tight. When someone has a heart attack, their chest often feels tight. Stretching would not be an appropriate solution to either one of those issues. 

The problem with this assumption that tightness means we need more motion is that many of the common stretch prescribed for the various structures our the hip place the hip joint in those irritable positions. While soft tissue mobilization can feel good briefly, we want to solve the underlying problem.

Listed below are four common themes I generally go through when runners come in with painful hip impingement.  


Symptomatic FAI can refer in a few different ways. Because of this, we are often quick to associate some lower extremity “tightness” as a cause of this pain. FAI can refer to a few common areas. Here’s the narrative most providers tell patients. 

Lateral Hip Referral

“You have a tight IT band. Do this stretch.”

Anterior Hip Referral

“You obviously have tight hip flexors. Do this stretch.”

Groin Referral

“Wow. You have really tight adductors. You need to stretch those out.”

Posterior Thigh Referral

“You have the tightest glutes I’ve ever seen.”  

Here’s the deal. If any of these stretches feel great, have at it. The positions of these very common drills are VERY close to the provocative positions shown in the first video. Instead of cranking into irritating positions, focus on easy, mid-range movements throughout the lower quarter. Remember, this is a tissues sensitive problem, NOT a mobility problem.

Do This Instead. 

The goal here is not to achieve greater ranges of motion. We are trying to get someone comfortable with movement from the lumbar spine, pelvis, and hip. 


Quit checking to see if something still hurts. Leave it alone, let it calm down, and then work back into those positions and movements. Leave it alone if it hurts to stretch into hip extension, adduction, or any other motion. 

Patient: “I really feel it if I move my hip like this.”

Me: “Ok, don’t do that.”

That seems like straightforward advice, but many people find themselves checking to see if something is still there. My solution is if you feel like you need to stretch, do five bridges instead and focus on keeping tension in your hip musculature.


Because of the low ROM demands of running, we have to be diligent about what positions we are putting the hip in the daily activities and exercise selections. Running usually isn’t a big irritant. The hip is probably closer to those impingement positions with things steps, low squatting, sitting, or crossing your legs. We need to closely look at activities during someone’s day to determine if this is a problem with running or with other activities that put the hip in greater ranges of motion. We have to be diligent in examining factors outside of running. 


Many runners could stand to improve their hip strength. We need to make sure we choose exercises that relate to running. A big reason I believe many runners use these drills is because of their ease of use. You do not need equipment and can do them anywhere.

Many of the common hip exercises are close to those provocative positions. The FABERS test is similar to the clamshell exercise, which might be the exercise runners are prescribed the most. Doing these exercises does not guarantee you will make the hip angrier, but there are better options. 

Clamshells (Sloppy Version)

The FABER assessment places someone’s hip at the end-range of hip external rotation, while also incorporating hip flexion and abduction. That’s that same position as the clamshell exercise.  

Quadruped Hip Extension (Sloppy Version)

We see those same problems with exercises on our hands and knees. Almost every high school team I have worked with does Myrtle Drills, a series of hip strengthening drills in quadruped. These are also often featured in prominent running magazines, blogs, etc. These are hard to do well and can easily keep an angry hip cranky. 

We want to improve the strength and capacity of both the hip musculature and the rest of the lower extremity. Muscles do no work in isolation when it comes to running, so the focus should be on building up the abilities to the entire lower extremity in running specific positions instead. I often prescribe these exercises in more “hip-friendly” positions as we progress back towards activities.

Bilateral Bridges

Lateral Toe Taps

Questions? Comments? Let me know! If you found this helpful, be sure to sign up for my newsletter below, and check out the next post in this series on how I progress exercise with FAI patients to get them back to running. Thanks for reading!

Nathan Carlson

Part I: Initial Management of FAI in Runners

Part II: Loading Progressions

Part III: Plyometrics, Training Progression, and Running Mechanics

Part IV: Long-term prevention, Strength Training, and Drills

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