The Hips Don’t Lie: Medial Collapse and Running-Related Injuries
As runners, how many times have you heard fellow compatriots complain about those darn shin-splints, or that pain in the lower leg that just won’t go away (i.e. compartment syndrome), or that niggling knee pain that just seems to hang around for what seems an eternity? If you have experienced one of these injuries, or know of someone who has, then you understand how frustrating it can be and how long it could potentially keep you off the road or trail.
Currently, the United States and arguably the world are undergoing what we may call the ‘second fitness boom’. Ditch the Jane Fonda-type headbands and spandex, slip on a pair of running shoes and luminescent moisture-wick management gear and we find many similarities between the then-vs.-now fitness booms. With 16 million Americans running 3 times per week, a 300% increase since 1999, one is able to track a concurrent string of injuries associated with this boom, with the most common occurring in the knee (50%), lower leg (26%), foot (14%), ankle (11%), and hip/pelvis (9%). Moreover, many runners are injured 12-16 weeks before a targeted race, with novice runners being 2.5 times more likely to develop some sort of injury during this period. Their appears to be a large variation between genders as well with females being more prone to specific running injuries than men, such as patella femoral pain (62% vs. 38%), tibial stress fractures (73.6% vs. 26.4%) iliotibial band syndrome (62% vs. 28%), with the balance of Achilles tendinopothy being quite similar between men and women.
What causes these injuries? Much of the research done has focused central psychosocial factors (such as life stress, lack of sleep), quality of tissue (muscle vs. fat), and genetics. However, the two most prevailing risk factors are running biomechanics and training loads.
Risk Factor #1: Training Loads:
It seems obvious that the age-old mantra ‘too much, too soon’ could lead to injury, but often us runners get carried away with our training, particularly at the beginning of the season when we are super excited to get going. However, we are constantly performing a balancing act between our ability to adapt to load versus the actual biomechanical load. Too much stress when we are not adapted for it, and we begin to break down, not enough stress, and we don’t improve. This is where periodization of your training plays a critical role, i.e. the planning of your training cycle into clearly-defined blocks of different intensities, volumes, and overall. Research has shown that one of the best protections against running-related injuries remains a consistent history of aerobic training; i.e. a previous history of training. An elite athlete may well be able to handle a sharp increase in training load in a very short period of time, as they would have years of training behind them, while a beginner or even intermediate runner may not be able to withstand the same load. Furthermore, the composition of one’s tissue can also play a role, with a more muscular physique being able to withstand a greater increase in load than someone with a higher percentage of body fat.
Risk factor #2: Biomechanics
While training load certainly plays a significant role, poor running biomechanics will still put one at risk of injury regardless of how careful one is in building their aerobic base. Generally, a running coach or biomechanics specialist would ask you to hop on a treadmill and run at a comfortable speed (I can imaginarily hear each runner groan while they yell out ‘treadmill is not the same as road’ - but the research has shown that in fact, treadmill running is very similar to that of road running when examining kinematic patterns ) He/she will then usually take a video recording of you running, usually from the side and back, both with your whole body in the frame as well as close-up at your feet. There are a few key points which your coach will look at, namely; overstriding and medial collapse. Overstriding is when a the foot-ground initial impact is made with the heel, and the foot is generally outstretched in front of the runner with the impact zone being in front of the hips - more in this in another article in the series. The other biomechanical focus point, known as medial collapse, is when the knees tend to fold in during the subsequent foot strike. A common secondary effect of a medial collapse is the dipping of the hips toward the side of the foot strike (Figure 1 A). This simple biomechanical observation has been linked to injuries such as stress fractures of the foot, piriformis and gluteal trochanteric bursitis, as well as gluteal tendinopathy. What is found is that the cause of this is neither structural nor strength-based, but rather motor control of the gluteal muscles. In a study conducted in runners with medial collapse, the researchers placed brightly-coloured stickers on the outside of the runners’ knees while showing a live rear video feed of their running. They were then simply asked to imagine that they are pushing their knees out toward the side walls (Figure 1 B). Astonishingly, the runner’s biomechanics rectified, and even more astonishingly was that they were able to maintain that form in real-world scenarios. The conclusion was that skill-orientated training, like the above, activated a portion of the motor cortex which allowed the runners to ‘learn’ a new technique of running and were able to cement that skill in their minds, much like riding a bike.
How to Use This in Your Training?
Firstly, if it aint broke don’t fix it. Translation: If you have been injury free for years and have been improving nicely, then it’s best not to meddle with running form. If you are like me and have had more injuries than you can count on one hand, then it may be best to get someone to record you running, or set up a camera yourself. Record your running from behind you with your entire body in frame and specifically look for the medial alignment of your knees. If your knees collapse inward then it might be beneficial to rectify this. Set up a camera behind you and link it to a screen (or simply record yourself running and look at yourself afterward). Step back on the treadmill and set it to a comfortable walking pace. Imagine that you are pushing your knees outward while walking. You will likely feel rather awkward, but this is simply the mind-and-body being slightly confused at your new form. After you feel comfortable that your form is correcting and can see this in your recording, pick the speed up to an easy jog and repeat until you are able to maintain form. Finally, take your new-found skill to the roads and focus on your form. It is best to develop some cues such as ‘knees out’ and ‘hips level’. Hopefully your injuries will be less frequent and you will be on your way to becoming a more efficient, injury-free runner.
Take Home Task
Next time you are out for a run, take not of how your knees feel. Do they fall inwards? If so, does your foot flatten out when it strikes the pavement? Also, which part of your foot hits the ground first: heel, forefoot, or rather both heel and forefoot simultaneously?
If your knees are aligned, you land on your fore-or-midfoot, and your foot arch is strong and doesn’t collapse - great!
If, like many of us, the your knees fall in, then try focusing on keeping them aligned. Really focus. Imagine that you are watching yourself running toward yourself, and you can actively see your knees. Now focus on keeping them from falling in. Also, focus on preventing your foot from flattening out on each step. Focus on landing with your feet directly below your hips; not in front, not behind, but below. This will automatically force you to land more toward your forefoot.
Test it out intermittently during a run. Naturally, your mind will drift, but whenever you feel your form fade slightly, remind yourself to keep your knees aligned and your feet strong.
Over time this will become natural, and you should be on your way to becoming the natural athlete that is within you.
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 Souza RB; an Evidence-Based Videotaped Running Biomechanics Analysis; Phys Med Rehabil Clin Am. 2016; 27(1): 217-236