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


The body of research on FAI (hip impingement) has grown substantially over the past few years.  Along with that, the runners and triathletes that come through my doors with this diagnosis seems to be growing as well. The explanation most runners are given is that you have a misshaped bone in your hip, and/or pelvis, which is leading to irritation and possibly a labral tear, cartilage problem or other hip issue. So lets 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 and serves as a great template for understanding what FAI actually is and how to best manage 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 or groin

3. Positive clinical signs (often pain with hip IR, + FABERS, Scours testing)

Basically you have to have pain with certain 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. 

This is important because if someone's hip anatomy is not "normal" it does not mean there is a problem. There are a lot of people with "abnormal" hip architecture that don't have pain and can perform at extremely high levels of sport. Having hip anatomy that is different than "normal", whatever that is, is not a 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, more than likely the assessments in the previous video are not going to feel great. I'd argue that some of these assessments would not feel great on a lot of people without complaints of hip pain.

When the tissues of the hip joint are irritated, they generally don't like these positions. 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 it's end range of motion, bone, soft tissue and other structures are going to push against each other. 

Whether we run too much, don't allow proper recovery, or are a little overzealous with our strength exercises, these impingement positions can get irritable just like your skin gets irritated when you have a sun burn. Load management is important in all running related injuries, whether we are dealing with tendinopathies, bone stress injuries, etc. That load management needs to be the focus of management and not necessarily someone's structure. 

How does this relate to running? 

FAI often presents itself as "motion-related pain". Those motions are often end-range positions of the hip. Many FAI patients can get through daily activities that don’t put their hip into greater hip ROM. It is when they have to sit, pick up their kids, or go up steps that they get push back.

Luckily, the flexibility demands on the hip with running are really very small compared to other sports. Running is inherently a mid-range activity. If we look at the work of Novachek, these are the ROM requirements for the hip and running. 


This is not to say that you might want a little more wiggle room than the numbers listed above, but you generally don't need that much hip mobility/flexibilty for running. 

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. Whether it's manually working on someone's hip, or having them perform hip stretching, most patients I see will be doing some form of exercised focused on managing tightness with end-range hip activities. There are lots of 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 is having 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 stretches prescribed for the various structures our the hip place the hip joint in those irritable positions. While soft tissue mobilization can certainly make things feel a little better, we want to make sure we are actually solving 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. While there are many places FAI can refer, these are the most common spots and the drills runners are often prescribed. 

Lateral Hip Referral

"You obviously 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 not a mobility problem, it is a tissue sensitivity problem. 

Do This Instead. 

The goal here is not to achieve greater ranges of motion, it is to get someone comfortable with movement from the lumbar spine, pelvis and hip. Easy motion that transitions into weight bearing drills. 


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

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

Me: “Ok, don’t do that.”

That seems like really simple 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.


We need to take a very close 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. 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. Aside from running on inclines, and running at greater speeds, the hip is probably going to be closer to those impingement positions with things like, steps, low squatting, sitting or crossing your legs. We have to be diligent in examining factors outside of running. 


Many runners could stand to improve their hip strength, but we need to make sure the exercises we choose relate to the demands of the sport, and are appropriate if someone is dealing with pain. A big reason I believe many runners use these drills is because of their ease of use. You do not need any equipment and they can be done anywhere.

Many of the common hip exercises are close to the provocative positions I keep coming back to. The FABERS test is a very similar position 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 I feel 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 position is the same position achieved with the clamshell exercise.  

Quadruped Hip Extension (Sloppy Version)

The same ideas discussed with the clamshell are present with quadruped drills as well. Almost every high school team I have worked with does Myrtle Drills which is a series of hip strengthening drills in quadruped. These are also often featured in prominent running magazines, blogs, etc. If we look again at the position this is placing the hip in, and how easy it is to combine lumbar, pelvic and hip motion together, this type of drill might just be further irritating the situation. 

We want to improve the strength and capacity of both the hip musculature as well as 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. As simple as it seems, I often prescribed these exercises which are in more "hip-friendly" positions as we progress back towards activities

Bilateral Bridges

Lateral Toe Taps


Questions? Comments? Let me know! The next post in this series will go over how I go about loading FAI patients to get back to running. Thanks for reading!

Nathan Carlson PT, USATF


Part II: Loading Progressions

Part III: Plyometrics, Training Progression and Running Mechanics

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