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Is Running on a Treadmill Bad for your Knees?


Running is one of life’s joys, and in a perfect world we would all have access to beautiful parks, woods, and fields where we could run surrounded by nature. But this is not always possible, particularly if you live in an area where it rains pretty much constantly. Luckily some genius invented the treadmill, meaning that we can all see the benefits of running without having to leave the house.

Treadmills really are fantastic machines, and they have so many health-related benefits. However, many people claim that they may cause knee pain or even injury. In this article we will be examining the facts and attempting to answer the question “Is running on a treadmill bad for your knees?”.

Running and Your Knees

The knee is what is known as a modified hinge joint, it attaches the femur and tibia as well as the femur and the patella (knee cap). The knee allows you to flex and extend your leg, it also allows a slight lateral movement to the left and right. The knee allows you to walk, run, jump, squat, sit and stand up, and many other movements.

As such, keeping your knee safe and healthy should be of paramount importance. What you need to understand about knee injuries (or any sports-related injury for that matter) is that there are two types. There are overuse injuries (also known as chronic) and there are acute injuries (caused by accident such as falling over).

Running has one of the highest incidences of injuries, more than most contact sports! This is partly due to the repetitive nature of running, and partly due to a larger percentage of runners being untrained (first time exercising). 

According to a 2013 study, 25% of the population has suffered or is currently suffering from patellofemoral pain syndrome, which is an overuse injury that represents 40% of knee issues among people who participate in sport [1]. 

Patellofemoral pain syndrome is also known as “runner’s knee” and is caused by an imbalance in the muscles that surround the knees or bad running technique. 

Another common knee injury is IT Band Syndrome, the iliotibial band connects your knee to your hip and runs along the side of your leg. When the IT band becomes tight it can lead to knee pain. This isn’t technically a knee injury, as it is the IT band itself that is the cause. However, this is such a common cause of knee pain that it had to be included.

More serious knee injuries such as injuries to the Anterior Cruciate Ligament (ACL) or Posterior Cruciate Ligament (PCL) are caused by mistake rather than overuse. Changing direction too fast, stopping abruptly, or landing badly after a jump can cause these injuries.

There are lots of different knee injuries and the causes of these injuries are varied. Most of them seem to have several common themes though. Overuse injuries are normally caused by either bad technique or muscular imbalances. While acute injuries are usually caused by accidents that can occur while running. 

We will now take a look at whether running on a treadmill can increase or decrease the likelihood of these injuries occurring. 

Is Treadmill Bad for your Knees?

There are several theories as to why a treadmill may be worse for you than running outside, the main theory is that running on a treadmill creates an unnatural running pattern which can increase the risk of injury. But this theory doesn’t seem to have much basis in fact. If you have a good technique while outside your technique should still be good on a treadmill. If you have a bad technique outside, then your technique on a treadmill should also be bad.

There is some evidence that running on a treadmill can influence your running technique, but none of the changes would affect knee health. People who run on treadmills tend to be more upright than people who run outside, but 1) this can be easily rectified by increasing the gradient slightly, and 2) it would not affect knee health positively or negatively.

The main causes of knee injury can still affect treadmill runners. Bad running technique will lead to an overuse injury, muscular imbalances can also affect your knee. Both of these issues need to be addressed, but no more so than if you were running outside. Acute injuries are actually much less common in treadmill runners than they would be in outdoor runners. 

Yes, there is the ever-present chance of falling off! But think of all the ways that an outside runner can get hurt. Tripping over a fallen branch, colliding into another runner, slipping on mud, hit by car, changing direction and causing an ACL injury … the list goes on and on. The chances vary from low to very low risk, but as you can see outdoor running provides many more methods of potential injury.

Can Running on a Treadmill be Good for your Knees?

Hopefully we’ve convinced you that running on a treadmill is no worse for your knees than running outside. But can running on a treadmill actually be good for your knees? 

Firstly, we should point out the obvious. Many knee injuries and knee-pain complaints stem from people being inactive and overweight. Carrying a lot of body fat can put a tremendous amount of pressure on your knees and other joints. 

Running on a treadmill can strengthen your leg muscles, which improves joint health and reduces the risk of injury. It can also help you to create a calorie deficit which leads to weight loss. Less body fat, less pressure on the knees. So, in a way, running on a treadmill is good for your knees. Though this could obviously have been said for running outside, or any form of cardio or resistance exercise.

Treadmill running does offer you more control over your running though, your stride length will be the same throughout, unlike regular running where many factors can influence stride length. There is also no downhill running or turning required. You don’t have to run around or through obstacles. This reduces the risk of acute injury. 

In many ways, running on a treadmill is safer than running outside, provided that you are comfortable with running on a treadmill and no how to climb on and climb off safely.

How to Reduce the Risk of Knee Injury on Treadmills

There are three things that you can do that will help you to reduce the risk of knee injury while running on a treadmill. The first thing that you can do is get your running technique analysed by a professional, this is the best way to avoid injury. If you have any glaring technical issues, then a coach can help you to fix them.

The second thing to do is to address any muscular imbalances through the use of resistance training. Have much stronger quadriceps than hamstrings? Well, performing hamstring-dominant exercises such as the Romanian deadlift or lying leg curl can help to fix this. 

If you’re not sure whether there is an imbalance or not you can perform compound lifts such as the barbell squat or leg press which work all of the leg muscles and will help to reduce imbalances.

The third thing that you can do to reduce the risk of knee injuries is to practice proper treadmill safety. Learn how to turn the machine off before dismounting, never jump on or off if the belt is running. Only use speeds that you are comfortable with, and make sure that any loose clothing is tucked in and shoe laces tied.

Is Running on a Treadmill Bad for your Knees? The Verdict 

There is a risk of knee injury when you run on a treadmill, as there is a risk of knee injury with any form of exercise. But is running on a treadmill bad for your knees? No, it is not. If anything, the benefits massively outweigh any drawbacks. 

Provided that your technique is sound, and that you have addressed any muscular imbalances, then a treadmill should actually lower your risk of injury compared to running outside. Not that outside running is bad for you either. Both forms of running have many health benefits that far outweigh any risks. 

Just ensure that the treadmill that you are using is made from a reputable company, is high quality, and is stable, and you can run for years with no issue. You can be safe in the knowledge that a well chosen treadmill is good for your knees, and not a threat.

Is running on a treadmill bad for your knees?