Will Training On A Treadmill Slow Me Down?

man training on a treadmill


By Simon Gould

When you run outside especially if you take part in races you begin to know your best time for a certain distance. The aim of many runners is to try and beat their best time. For this reason you don’t want anything that could possibly slow you down. Treadmills have a bad reputation when it comes to “proper” runners, they are boring and could they possibly be slowing you down?

Do you run slower on a treadmill?

Many runners have reported that they run slower on a treadmill when they do their normal run. Marathon world records are slower for the treadmill so may be there is some truth in that notion. Running on a treadmill is different as the “ground” moves beneath you and you are limited in your stride. Plus you have to concentrate to stay on.

The science actually says you use less energy when you run on a treadmill. So if you are of a scientific mind this does seem to be a conclusion. They tested runners doing the same speed and time of running inside and out and compared the VO2. This is a way of comparing how much energy is used when exercising.

A treadmill doesn’t have to slow you down

The only way it can slow you down is by you running slower on it. If you know your speed outside the replicate this on the treadmill. You may want to run on a 1% incline to replicate running outside and make it a bit harder. If you take your treadmills runs easier than those you do outside, then in time, your speed could be negatively affected.

You have to actively let it slow you down. Many athletes successfully use a treadmill when necessary without it affecting their performance. I’m referring to long distance runners. I certainly wouldn’t use a treadmill very often for sprinters. Don’t be afraid of using a treadmill and neglect it totally. There are times and places where it can be useful.

When to train on a treadmill

If the weather outside is that bad or you don’t feel safe at night and other reasons then a treadmill is ideal to keep your fitness levels up. You get that run you wouldn’t have been able to do if you didn’t have access to a treadmill. To make it similar to running outside it is recommended you set the incline at 1% for a similar cost in energy used.

There are circumstances when training on a treadmill is ideal and that is when you want to do some speed training. This is when the treadmill helps you run faster. By doing speed training you get your body used to exerting a lot more energy as you run and you’ll be able to do your normal runs quicker. We have 3 pages of speed workouts specially made for the treadmill:

Don’t rely on a treadmill for all your training

Running on a treadmill is different to running outside so run on it as little as possible. If you do most of your runs outside and like to have personal best times for distances, then don’t switch to, and run too much on a treadmill. If your personal best was measured from outside running then it makes sense to train your outside running to improve it.

It can be difficult if you’ve bought a treadmill or have a gym membership to avoid using one. Maybe you want to get the most use of it as you can and there are times when using a treadmill is a good idea. But it isn’t in normal training. There’s certainly no evidence that it does slow you down apart from certain runners saying it does for them.


We don’t really know if training on a treadmill will slow you down. For some it does and others it doesn’t. So don’t take the risk is our advice. Do the least amount of normal runs on a treadmill as possible, to the point where the question of whether it slows you down doesn’t enter your thoughts. As you don’t use it enough to find out.

Treadmills have their uses as we’ve covered. They’re great for beginners and sometimes with minor injuries experienced runners can find them useful as well. They come into their own when it comes to speed work and we recommend you give it a try if you haven’t. The treadmill is by no means redundant but if you like to run outside for your training then stick to what you like doing and use a treadmill only when you have to.

Thinking of buying a treadmill? Here’s my favorite, I always recommend it when asked.

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