What does the evidence show?
What does the evidence show?
In recent years, debates about running form have tended to converge on two factors: cadence (are you taking roughly 180 steps per minute?) and foot strike (are you landing on your heel or forefoot?). This is understandable, because these components are easy to grasp and to measure. But running is an unexpectedly complex series of motions, and there are plenty of more subtle and idiosyncratic ways to get it “wrong.”
I put “wrong” in quotes there because I remain skeptical that there’s a universal “right” way to run. Still, it’s likely that some running styles leave you more susceptible to injury than others, even if demonstrating these links with scientific studies is logistically challenging.
Which stride parameters matter? That’s still an open question. But at a running science conference in Vancouver last weekend, I had a chance to hear Christopher MacLean, who heads the applied biomechanics lab at the nearby Fortius Institute, share his top four “clinical pearls.” MacLean and his team use a lab-grade force-sensing treadmill that costs hundreds of thousands of dollars, plus a ten-camera motion-capture system that produces a detailed 3D model of your running stride.
From the ground up, here are the four key warning signs MacLean has learned to watch for in runners.
As your foot leaves the ground, your big toe should bend upward by about 40 degrees relative to your foot. But in some people, the toe joint stays almost straight. That’s a problem because of the load it puts on the joint, which can eventually result in hallux rigidus, a painful form of degenerative arthritis that can require surgery to correct. It also forces you to alter your stride, which causes changes that cascade up through your legs and can lead to other injuries.
The challenge is that even sophisticated gait analysis won’t pick this up if you’re wearing shoes, since the toe angle is hidden inside. Instead, telltale signs include a hole worn into the insole of your shoe under the big toe, a pinch callus along the inner side of the toe, or a rotational wear pattern on the bottom of your shoe under the forefoot. The most straightforward fix, according to MacLean, is getting a shoe that fits properly and adding an orthotic or insert that elevates the other four toes. By taking pressure off the big toe, you allow it to flex more easily.
The giveaway for this one is that immediately after midstance—the point at which your knees are next to each other, if someone is filming you from the side—your heel is already starting to lift off the ground. That means your ankle isn’t bending enough, and as a result, you’re putting extra load on your forefoot, which can lead to foot injuries. You’re also upping your risk of calf strains and altering your stride in other ways.
The cause may simply be that your calves are too tight, in which case stretching your calves should help. It could also be a result of your foot structure. Some people have a foot shape that puts a greater than normal load on the forefoot, in which case making sure your shoe has a heel that’s ten to 12 millimeters higher than the forefoot is helpful. One change MacLean has seen in recent years is an increase in the number of trail runners who have turned an ankle at some point but haven’t rehabbed it properly, leaving them with a reduced range of motion. Massage can also help restore the full range of motion, he says.
The bending of your knee acts as one of the key shock absorbers that softens the impact when your foot hits the ground. MacLean says to think of how you’d try to land if you were jumping off a tree branch: You’d bend your legs. If your knee is bent by less than about ten degrees when you land, then the forces shooting through your legs are dramatically higher. The consequence: knee pain and increased risk of bone injuries like stress fractures in the shin.
One potential cause is that you’re overstriding—taking steps that are too long and reach out too far in front of you. If that’s the case, increasing your cadence, aiming for 170 to 180 steps per minute at your preferred running pace, might help. Alternately, it may be that you’re not driving your knee sufficiently forward during the “swing phase” when your leg is off the ground. In that case, trying to deliberately modify your running stride by focusing on knee drive may help.
If you’re watching a runner head-on or from behind, the waistband of their shorts should stay roughly parallel to the ground. If the waistband tilts back and forth (with the lowered side corresponding to the leg that’s off the ground), that suggests the hip muscles are either too weak or aren’t firing properly.
Hip drop is a problem because it messes up the alignment of the rest of your lower body, which is why weak hips have been associated with a variety of injuries, including patellofemoral pain (a common knee injury), iliotibial band syndrome, shin stress fractures, and even plantar fasciitis and Achilles tendinopathy.
If hip weakness is the issue, then strengthening the hip stabilizer muscles, particularly the hip abductors, may help. MacLean also sees this issue when runners have “crossover” stride. Imagine running along a straight line painted on the ground: If more than half of your right foot lands on the left side of that line (and vice versa), you’ve got crossover. The solution—easier said than done, admittedly—is to retrain your gait so you’re landing without as much crossover.
The next question, of course, is what you should do with all this information. An increasing number of places offer formal running gait analysis, typically costing a few hundred dollars. Alternately, you can try some DIY analysis with a treadmill and a smartphone. And wearables are starting to measure some useful stride parameters: Lumo Run, for example, offers a real-time estimate of hip-drop angle.
The biggest caveat, from my perspective, is whether these warning signs predict future injuries reliably enough to warrant proactive changes. I don’t know the literature thoroughly enough to say for sure, but I’m still a bit skeptical. My take would be that if you’re running happily without injuries, be very, very wary about messing with your stride. The hard truth, though, is that many (if not most) runners end up getting injured eventually. And when you do, looking for these warning signs may offer you some clues about what you need to fix to stay healthy next time.
My new book, Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance, with a foreword by Malcolm Gladwell, is now available! For more, join me on Twitter and Facebook, and sign up for the Sweat Science email newsletter.