Does running really destroy knee cartilage?

Does running really damage your knees and cause knee pain?

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A new study has found that running doesn’t actually damage knee cartilage, as so many of us have feared. Here’s why a frequent jog does your knees more good than harm.

One of the most common reasons I hear from people who ‘don’t’ run is that they have ‘bad knees’. Often, we’re talking about people in their late 20s and early 30s, who seem to have written off a lifetime of health benefits already. 

Running is a high-impact sport. No matter how slow you go, each step is akin to a little jump – and that puts a lot of force through each joint. That’s why we’re forever banging on about the importance of doing isometric work – single leg deadlifts and good mornings.

So, does running really damage our knees and should we avoid jogging if we do have knee issues?

Not according to a couple of new studies. The first, published in the Journal of Sports Sciences, compared the cartilage of 30 university runners, 30 recreational runners and 30 non-runners. Researchers found no difference in the thickness of participants’ cartilage.

The second, this time in Sports Medicine examined hte results of 43 studies looking to running and joint health. It found that any cartilage recovers and adapts after just a single bout of running, and that repeated running doesn’t denigrate the quality of knee or ankle cartilage. 

There’s plenty of evidence to support the idea of running as being good for our knees

There’s so much evidence out there to dispel the myth that running is bad for our knees. According to a 2017 study, published in the journal Arthritis Care Research, running isn’t linked to knee pain or arthritis and may actually reduce knee pain in people who live with such issues. 

The idea that running is responsible for knee damage has also been disproven. An analysis of 28 studies concluded that there was strong evidence to link physical activity with stronger knee tissues and that running can actually keep us mobile for longer, reducing our risk of falling as we get older.

“Running is always believed to be damaging because of the impact – but impact itself isn’t damaging on the body, it’s how we deal with the impact that could be,” explains Brett Gatward, soft tissue therapist at Start Running Stay Running (SRSR).

To improve how your body reacts to that impact, he recommends making sure that you gradually increase your volume of running (eg not going from 10km a week to 30km in a month!), taking adequate rest and focusing on good nutrition.

“If I had a pound for every time someone told me running is bad for your knees, I’d be, well, probably buying more running shoes,” says writer, presenter and licensed England Athletics coach, Kate Carter. “You can kind of see the logic – people clearly think that pounding the pavement is slowly disintegrating their joints until arthritis inevitably sets in. In fact, some really big studies have looked at this and concluded the opposite: the incidence of arthritis is significantly lower in runners than in walkers.”

Carter cites one study that suggested that it might be that running tends to lower BMI more than walking, and that lower body weight is the key to preventing arthritis. “The single largest risk factor for knee osteoarthritis is obesity. There’s no evidence that running is bad for you.”

Not all pain is damage

Gatward also makes an interesting point about pain. He tells Stylist: “There’s a belief that pain is damage, but pain can also just indicate that the body is seeing a movement as a threat because you’re not used to that particular movement in the way you’ve done it. You can have pain with no damage being done to the body.”

And that’s something that many non-runners struggle to understand. For those of us who run regularly, the pain cave is a common foe; very few of us can run long distances without some instance of pain cropping up. Usually, it’s temporary and just part of the process; it’s when you’re in pain after your run that you might need to worry.

But knees aren’t exempt from injury

Of course, running can exacerbate issues if you already have them so a big part of this is about knowing your own body and pain threshold. A 5km might be painful if you’ve never run before, but you shouldn’t be hobbling around after 30 minutes of cardio, or feeling any kind of stabbing pain beneath your knee cap. 

“Knees aren’t exempt from injuries and it’s not a good idea if you have pre-existing knee pain to suddenly start running,” Carter explains. “‘Runners knee’ is a pretty common running ‘overuse’ injury, usually caused by doing too much, too often too soon. For that reason it’s often something beginner runners might suffer from – it’s not that they are doing anything wrong, it’s just that obviously, your body is doing something it’s not done before so it can be a shock to the system! 

“Most of the time it’s not terribly serious, and goes away by itself if you rest properly, alongside RICE (rest, ice, compression, elevation).”

When I first seriously got into running, I went from a bi-weekly 5km to running 10km on a treadmill every day after work. Predictably, I ended up at the physio with a baker’s cyst bubbling behind my knee. My knee wasn’t painful as such, but felt odd – like something was getting in the way of it bending properly whenever I tried to walk. It was a classic case of ‘too much, too soon’, with absolutely no attention paid to strength or balance work. As well as needing to have the knee drained on a weekly basis (grim!), I was given lots of rehab homework, including banded squats, crab walks and single leg balances. To this day, I still brush my teeth standing on one leg.

Gradually increasing volume and distance, and making sure that you vary the types and terrains of run is also something that SRSR’s strength and conditioning coach Simon Evans agrees with: “When working with athletes in the past, I’ve noticed that having more flexibility in the tendons can help with any excess impact.”

If you do have pre-existing knee pain, Carter recommends talking to a physio or doctor first because how you might be able to cope with running will differ from person to person. 

How to make your tendons more flexible

Well, your best bet is to do plenty of strength training. When you lift heavy things (whether that’s your own body or a pair of dumbbells), you’re not just building muscle but also putting stress on tendons. To repair damaged tissue, blood carries nutrients around to the cells. Tendons have less blood flow than muscle so they take a lot longer to respond to training than, say, your biceps. In fact, one study found that it takes around two months of resistance training for any changes in the Achilles’ tendon to happen. 

To really strengthen and lengthen tendons, you want to stretch properly, moving through your whole range of motion. That might be a standalone yoga or mobility session, or a pre-workout prep. You then need to make sure that your regime has a good mix of explosive movement (speed training), single leg exercise and slow, heavy weight training. The slower you move in the eccentric part of an exercise (the lowering bit of a deadlift, for example), the more tension the tendons will be under. It’s that which will make them more flexible.

If you are in serious pain, absolutely do get checked out by a physiotherapist to rule out things like plantar fasciitis or shin splints. If, however, you’re avoiding running because you think it’ll damage your knees but haven’t had it ruled out by a medical professional, give it a go. 

Keep your sessions short and slow. Make a commitment to stretch and strength train and after a few weeks, assess whether the running feels good or not.

Improve your running and reduce injury by joining our four-week Strength Training for Runner’s programme.

Images: Getty

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Miranda Larbi

Miranda Larbi is the editor of Strong Women and Strong Women Training Club. A qualified personal trainer and vegan runner, she can usually be found training for the next marathon, seeking out vegan treats or cycling across London on a pond-green Tokyo bike.