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Is Running on A Treadmill Bad for Knees?

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Running on a treadmill is one of the most popular forms of cardio, but it’s not always good for your joints. Running is tough on the body in general, and the treadmill repeatedly hammers the same areas over and over again. But is running on a treadmill bad for knees?

Running on a treadmill is not any worse for your knees than running outside. By using the proper equipment, focusing on running posture, exercising in moderation and doing a good warm up and cool down, your knees and your body will hold up very good to running.

Important points about biomechanics, how to avoid knee pain on the treadmill, and some tips to help you do so will be covered below.

man running on a treadmill

Is Running on A Treadmill Bad for Knees: Inside vs Outside

Running has many benefits including improving fitness levels and reducing stress levels, as well as being an effective form of weight loss. But if you aren’t careful with how you do it, running can cause serious joint pain or damage which could lead to surgery down the line.

The repetitive motion involved in running – up-and-down – puts pressure on your knees while they bend back and forth. While the literature isn’t consistent, it does show there isn’t much of a statistical difference in knee strain when looking at running outside vs running on a treadmill in relation to knee health or overuse knee injuries.

Biomechanical Differences in Running: Treadmills vs Outside

people running on treadmills

One study from 2009 set out to look at the differences in the biomechanics between runners using a treadmill vs the great outdoors. It didn’t conclusively find evidence treadmills are more dangerous, but there is an issue with foot strike on the treadmill vs running naturally outdoors that is quite interesting.

On a treadmill, people tend to heel strike less (especially when barefoot) and strike the belt with the forefront of their foot. This may be a good thing to help protect the knees according to a study from the Journal of Orthopaedic & Sports Physical Therapy in 2014.

“Specifically, converting from a rearfoot to a forefoot or midfoot strike pattern has been promoted as a means to reduce the peak impact force, loading rate, and knee extensor moment.

How to Avoid Knee Pain on Treadmill

While knee pain isn’t specifically tied to treadmill running, it does come with the same risk as running outside. Some experts think that running with a moving belt may increase the likelihood of injury because the treadmill belt pulls your feet back as you run, which also puts strain on the knee joints.

One benefit of treadmills is that they offer more cushion and flex than running outside on surfaces like concrete, pavement, and even grassy ground. Each time your foot strikes the surface, forces are applied to the foot, ankle, and knee. This can lead to healthier knee cartilage and healthy knees over time.

These forces are largely dependent on a few factors:

  • What part of the foot strikes first
  • If the knee is extended
  • Your body posture

If knee pain is a persistent problem on the treadmill or outside, one recommendation is to try to lean slightly forward when running. This will encourage you to switch to a more midfoot or forefoot strike, instead of a heel strike, which will ultimately help reduce tension on the knee.

5 Tips for Helping Avoid Knee Pain when Running on A Treadmill

We’ve put these tips together based on the research we have cited earlier, our own experience, and various other online resources that look into these interesting topics.

1/ Running Posture

Running may seem simple, but it is quite a complex process. There are so many muscles, joints, ligaments, and a host of other things involved that all have to work well to make it successful. Your posture has a huge influence on those things.

It’s important to make sure you are running with the correct posture.

Here are a few tips:

  • Stay erect – (straight up and down) with a slight forward lean
  • Engage your core – a tight core helps hold your spine in place and make sure you’re movements are efficient
  • Use short strides – shorter strides help avoid knee extension and encourage your body to use correct posture without over-extending. This may help you foot strike more on the forefront of your foot which will help with knee pain as well.
  • Try to avoid the handrails – avoid holding the handrails. This will affect your posture and not leave you in an optimal position for running correctly.

2/ Use the Proper Equipment

We have outlined some thoughts on what features should be sought after when picking a treadmill to run on. Equally important are the shoes you wear.

Make sure you have the correct setup to help set yourself up for success.

3/ Incline – Good or Bad?

A slight incline is a good thing. Running with even as slight of an incline as 1% will help with knee flexion and overall knee pain. While not necessary for all people, if you’re noticing your knees are sore, tight, or inflamed after running, try to add a bit of incline to your next run.

It can also help mimic running outdoors more accurately than simply running at 0 degrees all the time.

4/ Exercise in Moderation

Sometimes the issue isn’t biomechanical or equipment-related – it’s simply a person pushing too hard. Our bodies need to adapt to exercise. This includes strengthening our ligaments, muscles, joints, etc.

Bonus Tip: Make sure to drink plenty of water as dehydration can cause inflammation in the joints due to a lack of lubrication.

5/ Proper Warm-up And Cool Down

It’s important to properly warm the body up before strenuous exercise. If you’re one of those busy people who jump on the treadmill at 7mph and push themselves to the end, you may need to rethink that strategy.

If every run is a tempo run, you may need to cool your jets a bit.

Especially as we get older, a good warmup becomes more important to successful, long-term exercise goals.

Is Running on A Treadmill Bad for Knees?

treadmill bad for knees

Ultimately, running on a treadmill is no worse for your knees than running outside. There are inherent risks with any physical activity, however, when done safely and appropriately all of those risks can be mitigated and the exercise enjoyed without negative side effects.

Contrary to treadmills being bad for your knees, they may help relieve knee pain due to naturally changing a person’s foot strike and providing a softer landing of reach step reducing overall forces on the knees. If you’re having consistent pain when running on a treadmill, it may be time to ask yourself if you’re running too much.

Is Incline on Treadmill Bad for Knees?

According to this study, the kinematics of the knee joint are highly affected by the level of incline.

“This study showed that the kinematics of the knee joint are significantly altered when running on a laterally inclined surface.”

Running on an incline does help relieve pressure on the knee, even at very small levels of incline. This is great news for treadmill runners. A 1% incline can also help mimic running outdoors. If your primary running, or racing, is done outdoors, then adding the slight incline will help accomplish several things at once.

“Even a 1% incline levels out the surface beneath you, relieves the pressure from your knees, and places the workload on the glutes and hamstring muscles,”

Dr. Plancher

Common Knee Injuries for Runners

Over time, all of this pressure and repetitive motion can lead to problems such as:

Patellofemoral pain syndrome (PFPS)

Also known as “runner’s knee,” is a condition that affects the cartilage under your kneecap. Symptoms include pain around or behind the kneecap, stiffness, popping, or grinding sensations.

Lliotibial band syndrome (ITBS)

This is a common injury among runners that causes pain on the outside of the knee. The iliotibial band is a strip of tissue that runs from your hip to your shin and helps stabilize your

Meniscal Tear

The meniscus is the cartilage that protects your knee. Running may put pressure on the joint, causing this cartilage to break down. A popping sound marks the abrupt traumatic meniscus tears that commonly occur in younger athletes and are characterized by a cracking noise when they are damaged.

Repeated stress over time may lead to degenerative meniscus tears, which typically affect individuals in their 40s and 50s. Both forms of meniscus tears can cause joint pain, edema, and “locking” of the joint.


Whether frequent running causes OA is unclear, however, some experts believe that the continual strain on the knee joint caused by running might speed up the angular deformity.

Knee osteoarthritis consists of aching, stiff, or swollen joints that hurt when exercising or after inactivity. While squatting, climbing stairs, and sitting still for long periods may all cause achy knees.

Patellar Tendinitis

Patellar tendinitis is an overuse condition of the patella tendon that runs from the patella to the shin bone and causes discomfort in the front of the knee, lower kneecap, or bony region just above the shin.

Pain can range from a mild ache while exercising to severe agony during daily activities. Swelling, redness, or warmth may also be present. This type of damage is prevalent among runners who frequently descend hills or make many starts and stops when running.

What to Look for In a Treadmill if You Have Knee Problems

Woman with Knee Injury on Treadmill

If you struggle with knee problems, there are a few things to look for in a good treadmill to make sure it doesn’t get worse:

  • Shock absorption – many treadmills have built-in shock absorption. How soft you want your running surface is a matter of preference, but generally, higher-end treadmills have more ability to absorb shock and reduce impact to the ankles, knees, and hips while running.
  • Get a wide belt – a wider belt will give you the maximum area for foot placement. This will help you run with a more natural gait, therefore, decreasing the chance you modify your form causing more issues.
  • Variable speed – make sure the treadmill has various speed settings. Most treadmills do, but some don’t offer as wide of an array. You want to be able to run comfortably, at your own pace, without having to adjust to the features (or lack thereof) of the treadmill.
  • Incline options – make sure the treadmill has several incline options for the same reason as above. Sometimes a little more or less of an incline can help reduce the strain on the body.
  • Get the right pair of running shoesrunning shoes are an important consideration when looking at the entire system handling the kinetic energy of running. A good pair of treadmill running shoes will help relieve some of that issue.

The impact of running on a hard surface like concrete can be much harder on your joints than running on a softer surface like grass or dirt.

Tip: If you do choose to run on a treadmill, make sure you’re gaining some benefit from a softer surface, a nice wide belt, good speed, and the right level of incline to maximize the benefit and minimize the strain.

How To Reduce Stress on Knees During Exercise

The right treadmill, and the right pair of shoes, can make a difference in knee pain when running indoors. However, if you’re looking to protect your knees to the maximum, try an elliptical machine.

Forces from an elliptical machine are only around 30% of those from treadmills. This treadmill alternative is a great way to still get a good workout without the same level of risk as running.

To Sum It Up

To succinctly answer if running on a treadmill is bad for your knees: no, it is not.

Treadmill running can be an enjoyable and effective way to augment your outdoor running. Heck, it can be your primary source of running work. That’s fine. While it isn’t inherently more dangerous (or honestly much safer) than running outside, it’s important to understand a few of the basic concepts described in this article. You can make sure to protect yourself and maximize your time spent racking up the miles on a treadmill in the future.

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About the author

Jasper loves to write about fitness, running, and anything else that gets him moving outdoors. He's an avid hiker, backpacker, and climber who loves to stay fit so he can make sure he's healthy enough to enjoy his favorite hobbies. He also spends time writing about his true passions in life.