The effect of running on your knees

Flexion and extension are motions that occur when bones move toward and away from each other by way of a joint.  The knee falls into the category of a hinge joint, which allows flexion and extension of the lower leg.

When you run and your knee flexes, your heel moves backwards, decreasing the angle between your lower and upper leg.  When you run and your knee extends, your leg becomes straight.


I hope I didn’t confuse you, but I need to make a point.  If you endure excess impact from years of running, your ability to flex and extend your knee will become greatly compromised.

This is largely due to wear and tear on your knee joint and the withering away of cartilage.  The best case scenario is you take preventive measures to decrease this impact and add years to your running life.  The solution may not be as complicated as you think.

Change the mechanics of your gait

Most people run with what’s called a heel strike.  Sadly I know of people who are actually trained by experts to run this way.  Even more sadly, this running style makes Swiss cheese out of your knees.

My suggestion is to land with a forefoot strike, which takes a bit of time, patience and practice.  Instead of landing with your heel, land on the balls of your feet.  This doesn’t mean run on your tiptoes.  That will make you look foolish and it will wear out your calves really fast.  Land softly on the balls of your feet and either let your heels touch lightly or keep them just above the ground.

A second best case scenario would be to land with a mid-foot strike.  In this case, think of the bottom of your foot as a tripod. The heel and two metatarsal bones under your big toe and pinky toe form this tripod.  Land on all three areas simultaneously with every stride you take, which will distribute the force evenly instead of sending a shockwave up through your knees.

Get rid of the thick-padded shoes

You may think you are doing yourself a favor by getting the thickest soled shoes you can find, but you are actually doing an disservice.  These shoes give you the false sense of security that your heel will not get beat up when you land, and you are correct.  However your knee still suffers a tremendous amount of impact any way you slice it.

The second problem is, due to all that padding, your foot is very unstable when it hits the ground.  It’s like landing on a sponge every time you take a stride.  This instability causes your ankle to wobble.  When your ankle wobbles, it transfers lateral force to your knees which can devastate your connective tissue.

You are best served getting a zero drop shoe that has an even thickness sole from toe to heel.  Couple this with a forefoot or midfoot strike, and you’ll be in way better shape.  I actually run completely barefoot, but you may not be at that stage of hardcore just yet.  If you should be though, let me know and I can get you dialed in.

The only option you have with barefoot running is a forefoot or midfoot strike.

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Run on softer surfaces

Here is a big paradox.  The best conditions for me while running barefoot are smooth blacktop and concrete surfaces.  If you run conventionally though, this is not the best idea because the harder the surface, the more disruptive impact you will endure.  If you have the option, always run on softer terrain, such as dirt trails, grass, sand and fields.

Reduce your stride length

I don’t necessarily mean run slower, but just pay attention to the length of each stride.  If you extend your leg out really far, you will certainly land on your heel and cause excessive impact to your knees.  Practice taking shorter, quicker steps instead and watch how much of a difference that will make.  Once you master this technique you can easily increase your speed.

Head for the hills

Regardless if it is grass, gravel, concrete, asphalt or wood chips, running up hills will cause way less impact on your knees than running on flat ground.  This is just simple math.  Because of the inclined angle, your foot hits the ground a lot lighter, which takes stress off your knees.  In most cases, your heels don’t even touch the ground at all.

Find yourself some nice long hills to run up and have a field day.  If you only have one hill to work with, run up it forward, run down backwards and repeat multiple times.  This is a fun variation that will also spice up your workouts and keep them interesting.

The bottom line is, running can be enjoyed well into old age as long as you take the precautionary measures to keep your knees in top shape.  Play around with what I told you and report back to me with any questions, comments or concerns you may have.

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