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Are Treadmills Bad For Your Knees?

Are Treadmills Bad For Your Knees

Running on a treadmill remains one of the most popular forms of cardio exercise for weight loss, aerobic fitness and general well-being. People enjoy the convenience factor of being able to run indoors, especially during the cold winter months. The treadmill also allows you to control your workout more than running outdoors. But is your body paying a price for that convenience? More specifically, are treadmills bad for your knees?

In this article, I’ll use the latest research to answer that question. I’ll also compare treadmills with outdoor running to see which is better for your knees and show you how to reduce knee pain when working out on a treadmill. Read on to find out, once and for all, if a treadmill is bad for your knees.

Is A Treadmill Bad For Your Knees

So, is a treadmill bad for your knees? No –  in fact, running on a treadmill may be better for your knee joints than running outdoors. When you run outside, your musculoskeletal system is constantly having to adjust to the undulating terrain beneath your feet. You may find yourself running on hard surfaces, such as concrete, gravel and heavily packed earth. The constantly changing impact levels can be tricky to adjust to.

In contrast, running on a treadmill provides you with a uniform running surface. In addition, treadmills have built-in shock absorption to lessen the impact of foot strike. As well as literal shock absorbers, the best treadmills will have multi-ply running beds.

Running on a treadmill is actually more of a knee-friendly activity than outdoor running, especially for elderly people. The treadmill puts the user in charge so that they can control the gradation of the running surface as well as the speed at which they are running. The treadmill also eliminates such variables as wind and rain that may cause a person to fall or slip while running. Many outdoor running knee injuries are due to these factors.

The degree to which an individual experiences knee discomfort while running on a treadmill is largely due to their running style. So long as they are running with an upright posture and their foot strike contact is with the ball of the foot, rather than the toe or heel, they will keep knee impact to a minimum to prevent injuries.

If you are in the habit of landing on your toes, your knee will be more bent than it should. Due to the constant pace on a treadmill, this can cause more knee stress than if you were running outdoors. This, though, is not a fault of the treadmill. By correcting your running style so that you are striking more with the midfoot than the toe, you will be able to minimize the knee impact so you don’t feel pain in the knee.

Go here to find out how good a recumbent bike is for your knees.

Outdoor Vs Treadmill Running

Outdoor Vs Treadmill Running
A 2019 study, published in the journal Sports Medicine, compared the biomechanical impact of running on a treadmill with running outdoors. The study involved 33 participants, who had their lower body biomechanics analyzed while running on an incline, a non-cushioned treadmill, a quasi-constant velocity motorized treadmill and running outdoors. The results of the study were as follows:
  • The vertical knee displacement was lower on the treadmill than when running outdoors.
  • The less stiff surface of a treadmill belt makes it better than running on the road for injury rehab.
  • Higher muscle forces in the calf muscles were experienced on the treadmill.
  • Treadmill running produced a lower level of propulsive force than outdoor running.
  • Lower braking force was experienced on a treadmill compared with running outdoors.
The study concluded that running on a treadmill was slightly better for multiple joints, including the knees, than running outdoors. Of course, outdoor exercise allows you to breathe fresher air.

How The Treadmill Impacts Knees

The main reason that people may experience knee pain on a treadmill is that they are running at a constant speed while using improper running technique. The forward propulsion of the treadmill belt may reinforce this tendency to land on the toes. This can cause a jamming effect which puts pressure on the locked knee joints, leading the runner to experience knee pain.

While some people believe that running on a treadmill incline is bad for the knees, the opposite is actually the case. By setting the incline at a 1 – 2 percent, the knee will be able to land more naturally under the body, rather than completely straight.

Choosing The Best Treadmill Belt For Bad Knees

Choosing The Best Treadmill Belt For Bad Knees

The thickness of the belt is the biggest factor affecting knee health. It determines the level of grip and the degree of impact transfer from the surface, to the foot and up to the knee. There are three main treadmill belt thicknesses or plies:

  • Single Ply – this consists of just one piece of rubber.
  • 2-Ply – the belt has two layers, with the top being made of rubber and the underside consisting of a cotton, polyester and mono-filament combination.
  • 3-Ply – an extra layer of rubber is added to provide more cushioning.

While it would be natural that a 3-ply belt is best, that may not always be the case. The extra thickness of the belt puts more strain on the motor which may affect the smooth performance of the treadmill. The extra cushioning may also make the treadmill too soft to run on. As a result, a 2-ply belt is preferred for maximum knee protection.

Interested in how to clean a treadmill belt? Click here to find out.

How To Avoid Knee Problems While Running On The Treadmill

How To Avoid Knee Problems While Running On The Treadmill

Wear Good Running Shoes

You should always wear shock-absorbing running shoes when working out on a treadmill. Do not run in bare feet!

Exercise Correctly And In Moderation

Build your workout duration and intensity up slowly, adding about 5 minutes per week. Do not run beyond exhaustion and stop if you feel any niggly pain.

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Check The Incline

You should set the incline to between 1 and 2 percent. This will best simulate the real-world running conditions that our bodies were designed to operate in.

Do you need a mat for a treadmill? Click to learn more.

Warm-Up & Cool Down

Always start and finish your treadmill workouts with a 5 – 10 minute leading in and cooling down period. This will enhance lower leg blood flow, get your quad and hamstring muscles ready for the work to come and bring your heart and breathing rate back to normal.

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Keep A Correct Posture

Maintain an upright body posture, landing on the ball of your foot and swing your arms naturally at your sides.

Read more about how to run on a treadmill.

Myths About Running On The Treadmill

  • Running on a treadmill will cause knee pain – the reality is that a treadmill workout is actually better for healthy knees than running outdoors.
  • Holding the side rails will reduce knee impact – holding the rails will not reduce the impact but will compromise your running form.
  • Running on a treadmill is more dangerous than running outdoors – so long as you’re concentrating on what you are doing and not jumping onto a fast-moving treadmill, it is just as safe as running outdoors.

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Signs You’re Overdoing Your Workouts

  1. Sustained lack of motivation – if you can’t summon up any motivation for three days in a row, take a full week’s break from the treadmill.
  2. You are always getting sick – colds and other illnesses may be a sign of overtraining; take a break to give your body time to recover.
  3. Lack of energy – this is a sign that your body is worn out and in need of a rest.
  4. Losing a lot of weight – weight loss below your maintenance level is not healthy as it probably includes muscle mass. Make sure that you are replacing the energy expended on the treadmill with quality nutrients.

Which is better: an exercise bike or a treadmill? Click to read more.

Frequently Asked Questions

No, treadmills do not damage your knees. However, they may contribute to the tendency to run on your toes, which may cause knee joint pain. So long as you are using proper running form, with your midfoot striking the surface, you will not damage your knees. The treadmill cushioning will also reduce knee impact.

Yes, walking on a treadmill is OK for bad knees. The treadmill is constructed with shock-absorbing technology so the treadmill produces less knee impact than if you were walking outdoors. However, to lessen knee impact further, you should set the incline on the treadmill to 1 – 2 percent. This will provide a more natural running angle, helping the knee to move in a more biomechanically sound manner.

To protect their knees, treadmill runners should learn to run with good posture. You should maintain an upright body position and land on your midfoot rather than your toe or heel. Move your arms naturally and do not hold onto the side rails. You should also set the incline to 1 – 2 degrees to provide a more natural running angle.

The main side effect of a treadmill is that, due to the forward propulsion, there is a tendency to land on the toes rather than the ball of the foot. This is not good because it causes excessive knee bend. As a result, you should concentrate on landing on the midfoot rather than the toe when running on a treadmill.

Yes, curved treadmills are better for your knees than traditional flat treadmills. The curved treadmill is designed to take the pressure off your knees. Its unique curved ergonomics minimizes knee strain when you start building up the running belt speed. If you have joint issues, you should definitely give a curved treadmill a try.


So, are treadmills bad for your knees? No – research shows that treadmills are, on the whole, better for your knees than running outdoors. When you are running on a treadmill, though, there is a tendency to run on your toes, which is not good for your knees. By using proper running form, where you strike the surface with the ball of your foot, you will be able to enjoy all the benefits of a treadmill without compromising your knees.