At least once a week, a patient tells me a story about their bad knees and how it must have been due to all the running they used to do. This is while they are lying on their hospital bed, waiting for their knee replacement later that day.
In Australia, osteoarthritis affects one in five people, and that increases to one in two people over the age of 65 (Australian Bureau of Statistics). In 2016, 60,211 knee replacement surgeries were performed in Australia (National Joint Replacement Registry). That’s almost double the number of surgeries that happened in 2006 and every year it is rising.
So, as a 30 something-year-old who runs three times a week, should I be concerned that I am damaging my knees? Is running bad for your knees?
We already know that running has numerous benefits. It can help you lose weight, lower cholesterol levels, boost your immune system, fight depression, reduce stress and increase your overall mood. But for years the debate has been argued on whether or not running is bad for your knees.
Recent research has come back in favour of the constant ‘pounding of the pavement’. Running, when compared to a sedentary lifestyle, can actually help reduce the risk of developing osteoarthritis at a later age.
So, are you saying that running may actually bullet-proof my knees, rather than damage them with osteoarthritis?
Not everyone who runs is destined to get osteoarthritis. There are a myriad of confounding factors that may lead to this debilitating condition.
Let’s start with a bit of anatomy.
The knees sure do take a lot of pressure when running. Anywhere between five and twelve times your body weight in fact!
Your hip is made up of a nice ball and socket, your ankle is made up of a complex system of joints which help to dissipate forces throughout the foot, but the knees take the brunt right through its surfaces (no wonder that there is a common running injury called “runner’s knee”).
The femoral condyles (the end of the long bone in your thigh – the femur) are nicely rounded, and sit on top of the tibial plateau (the bigger of the two bones in your shin – the tibia) which is a flat surface.
At the end of each bone is a hard shiny surface of cartilage, which can wear down over time. Now, we add the shock absorption properties of the meniscus and you have a fairly standard knee unit – for simplicity, we will leave out a few other structures such as the patella and ligaments.
So, what happens when the shock absorption properties fail over time? Think of your car when its suspension springs get rusty. There are increased forces through your bony surfaces, and those hard shiny layers of cartilage start to wear thin – this is when osteoarthritis starts to kick you in the backside.
Wouldn’t it be best to limit all forces through your joints so you don’t even give them a chance to develop osteoarthritis?
In short, no!
Lifestyle factors play a huge part in whether or not someone will develop osteoarthritis, and it seems that a sedentary lifestyle will have a similar prevalence of osteoarthritis than someone who runs 90 km a week!
What does the research say?
This systematic review and meta-analysis – a very strong research design – looked to compare three groups of people.
- The competitive and high volume runner – professional athletes and people who compete internationally or run more than 92 kilometers per week.
- The recreational runner – most of us will fall under this group, from new runners to members of clubs who train a few days a week.
- Non-runner, or controls – those sedentary people we mentioned above.
They found that, out of over 114,000 people, the prevalence of developing osteoarthritis in the competitive runner was 13.3%, the non-runner was 10.2%, and the recreational runner just 3.5%!
What does this mean for you?
The benefits of exercise are numerous, and recreational runners have less chance of developing osteoarthritis compared to competitive athletes and sedentary people. According to the research, this is true for both males and females. There seems to be a sweet spot where doing too little and too much can put great strain on your joints, so get out there and get moving!
With the above research, it is hard to include injuries, so if you are carrying one, get on top of it before pushing things to breaking point!
Take Home Point.
Casual runners (who run less than 92kms a week) are less likely to develop osteoarthritis than a person with a sedentary lifestyle.
It is proven that people who are overweight are two times more likely to develop osteoarthritis and people who are obese are four times more likely to develop osteoarthritis. It is generally believed that injuries increase your chance of osteoarthritis, so if running is causing knee pain or injuries, make sure you see a good physiotherapist to assist you with your running.
Another proven way to lower your chances of developing osteoarthritis is to increase your muscle strength, so ensure you’re adding some resistance training into your sessions.
We use Formthotics™ in our shoes – an orthotic which gives you stability from the ground up and helps to support your running. Formthotics help align the body from the ground up, assisting with shock absorption and relief of pressure points with a more even distribution of weight across the foot surface, which is particularly important on hard surfaces. With Formthotics, your foot is supported in a natural posture, reducing fatigue, improving stability and function.
That is fine, we are not trying to convert people into being runners, we are just highlighting some of the research, which says that running is not as bad for your joints as it is presumed!
If you are still unsure, try biking or swimming – the cardiovascular effort is great and being relatively non-weight bearing exercises, you won’t have any trouble with your achy knees after those!
If worse comes to worse, and you do need a knee replacement when you are 70, perhaps we will find hope in this inspirational story from Roger Robertson – a 71-year-old runner who continued running after a total knee replacement.
Follow our Team Ambassadors, Jeremy and Joanna Duggan - Physiotherapists from Australia who also have a passion to travel the world and make adventure happen with major events - like climbing to the basecamp of Mt. Everest and running a marathon in Antarctica and so much more! You can follow their blog here: Coming Home Strong
*Please note this content is not personal medical advice and is intended for general education purposes only. Consult with your doctor, physiotherapist or surgeon before starting a running plan if you are worried about arthritis.