Is running really bad for your knees? A personal trainer explains…

I love to run. Seriously, I love to run. Getting up every day and running for hours would be paradise. But I can’t do that. I would break.

When I speak to people about running I’m often met with head shaking and concerned looks. “Running is really bad for your knees”. Or the elaborate appeal from authority “I know a physiotherapist and she said running will destroy your joints and you won’t be able to walk when you’re older”.

OK, so let’s push ourselves away from the table full of emotion and break down these claims. Running is fast jogging. Jogging is slower running. And both are just speeded up forms of walking with some bouncing thrown in. As with most things in life it is the quantity that can kill you. Everything – and I mean everything – is bad for you in high enough quantities. Hyper-hydration is the consumption of too much water over a short period of time. It can, and does, kill people. But don’t stress. We are talking lots of water. Back to the running….

To understand why running is both good and bad we need to think about what exercise is:

What does ‘getting fit’ mean?

Jogging on a bright November morningExercise is a stress (Google: ‘Eustress’). Jogging and running stresses the tissues in the lower body. Not just the muscles, but the cartilage, bones, tendon, ligaments, and even the skin (runners tend to have nasty thick clauses). If you run too much on your first day you might notice a blister on your foot. This means your skin was stressed past the point from which it could adapt. And it broke. But if you had not gone quite so far or for quite so long you would have found that the skin on your foot just got thicker and tougher.

That is what a callus is. It is the skins reaction to stress. It is protecting itself in case it encounters the same amount of stress again. And guess what? All your tissues have their own response to stress.

Your bones can become denser in response to stress. Think of the pounding shock-wave sent through your bones as your foot strikes hit the pavement. We call this type of bone adaptation ‘remodeling’ (Google ‘Wolff’s Law’). Your muscles will adapt to the stress of running by building more mitochondria (the microscopic powerhouses in muscles) and increasing the number of blood vessels feeding it (Google angiogenisis). They become more efficient at recycling calcium so your muscles can contract for longer periods of time. These adaptations are what we in the industry call “Getting Fitter.

When running ruins your knees

There is an exception here. The cartilage in your joints can remodel too but unlike the bone, which is stronger when it remodels, cartilage remodeling results in an inferior product (Google ‘Fibrocartilage’). This is why it is so important not to over-train. Once you damage that cartilage, you might not recover fully.

Knee InjuryI want to stress this point so I’ve coined the term “over running”. I have never heard anyone else use this term so I will claim it. I see “over running” often. Running/jogging is hard at first, but eventually most people adapt and it becomes enjoyable. Even addictive. It feels really good to run, so people do it more often or they go for longer and longer running sessions. When you increase either the lengths of your runs or how frequently you run then you can get hurt. Increase them slowly with plenty of rest days and your body will adapt. Increase them too quickly, and don’t rest enough and something will bust: one or more types of tissue will not be able to adapt in time and – boom! – like the blister, the tissue will break. Damaged cartilage, torn Achilles tendon, shin splints, (and tons of other problems) can arise. But they don’t need to happen. Chill out. Take days off. Train hard and recover fully before training again. Because exercise isn’t worth anything if you don’t recover from it.

Remember exercise is about adaptation. Not about burning calories. It is the adaptation to stress that makes you fitter.

Article by Matthew Linsdell

January 18, 2012

Matt is a certified personal trainer and has a degree in Environmental Science. He calls himself an evidence-based trainer, because training is a field which is littered with well-disguised pseudoscience – his emphasis is always on teaching the biology behind exercise. He lives at the edge of the beautiful and expansive Gatineau Park in Quebec and works across the water in Ottawa, Ontario. If he’s not out walking his two pit bulls, you’ll find him doing press ups with insanely large weights on his back. Follow Matt on Twitter at @smartfitmatt.

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4 thoughts on “Is running really bad for your knees? A personal trainer explains…”

  1. When will we get to see some pictures of the small exercise facility in Ottawa? Are you able to have any fun at all without the Old Ladies? Will we ever be getting an invitation to visit Ottawa or Montreal? Questions, Questions, Questions…..

  2. Interesting read. I have been a committed walker not aspiring to run because of my weight. I had established a weight goal that, should I meet it, would trigger me to think about running. But this article makes me think that I am wrong in looking at it that way. This article makes me think that it is not how much a person weighs but how they train that increases the risk. So if I were to throw a minute or two of running into my walking workout and increase it a little bit at a time I could make a decision to start running now?

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