How to Avoid “Runners Knee”
In my previous blog I talked about the simplest and most effective way for walkers to reduce impact to their knees and hips. So, in all fairness to you runners, this post is for you.
Since runners, as a rule, are a bit more injury-prone than walkers, the simplest way to avoid knee pain or knee injury is not as simple as it is with walking. I’ve read that running can increase your body weight upon impact by 6-10 times depending on whether you’re running on flat ground or running downhill. That’s an incredible amount of weight for your knees and hips to bear with every foot strike. So, it behooves us all to do everything we can to lower that multiple. If I weight 145 lbs. that means I’m putting 870 lbs. of pressure on my knees every time my foot hits the ground.
There are two reasons for this increase in impact to your knees. Part of that increase in weight comes from the fact that you’re leaving the ground between strides and as you return to earth, your body is accelerated by the pull of gravity. The other part of that weight increase happens because of the braking effect created if your foot happens to land in front of your center of mass. For most runners I’d have to say that is the biggest culprit of increasing impact.
So what’s the simplest solution?
Don’t step in front of your hips when you run. You heard me right… and you’re also correct if you’re thinking, “That’s easier said than done.” It’s not really that difficult to do, but it does take some patience and practice. It all comes down to learning how to run with a midfoot strike because it’s the best way to prevent your foot from landing out in front of your body. You can further reduce the amount of impact to your knees by landing with your foot even slightly behind your center of mass. This will minimize any chance of braking as your feet hit the ground.
If you’ve read the ChiRunning book you already know about landing with a midfoot strike and how that’s accomplished. If you haven’t read the book, I highly suggest you check it out. Another part of this equation is keeping your hips loose and your pelvis rotating. This will keep you running level across the ground and prevent the impact that comes from excessive bouncing.
If you can change where your foot lands and minimize your bounce you can seriously reduce the impact to your knees. I was recently tested at the gait lab at the University of Virginia and found that my vertical GRF (ground reaction force) was only 2.4 times my body weight. That’s a far cry from 6-10 times mentioned earlier!
My long range goal is, of course, to get that number down to zero… so I can run on water.
Posted in Technique