Treadmill vs. Running Outside: Which is Best for Runners?

How does running on a treadmill compare to running outside? Is one easier than the other?

It’s a common question and despite conflicting opinions, scientific research has shown that running on the treadmill is roughly the same as running outside if you make a few simple adjustments.

In fact, there are some types of workouts you can do better on a treadmill than you can outside.

However, running on a treadmill does have its disadvantages, and for some runners, a mile on the “hamster wheel” feels like ten miles outdoors.

So, in this article, I’m going to show you the potential benefits and negatives of treadmill running, help you adjust your workouts to make treadmill running equivalent to logging miles outdoors, and give you some tips to make treadmill running more “enjoyable” when it’s necessary.

What is the difference between running outside and on a treadmill?

We need to find out if running outside is better for us than running on a treadmill, or is it the other way around?

On one hand, with a treadmill, the belt is moving under you and there is no wind resistance for your body to counter, so it should be easier to run.

Theoretically, you could jump up and down on a treadmill and it would record that you’re running at whatever speed the belt is moving.

Outside, your legs have to propel your motion forward while pushing through the resulting wind resistance (however minor it may be).

Luckily, scientific research has proven that setting the treadmill to a 1% grade accurately reflects the energy costs and simulates outdoor running.

Therefore, by setting the treadmill to a 1% grade, you can offset the lack of wind resistance and the belt moving under you to make treadmill running the same effort as running outdoors.

Corroborating research has shown that VO2 max is the same when running on a treadmill compared to outside, clearly demonstrating that running on a treadmill is as effective as running outside.

Furthermore, research reveals that bio-mechanical patterns did not change when test subjects ran on a treadmill versus when they ran outside.

We can decisively conclude that running on a treadmill has the same effect as running outside when running at a 1% grade.

When is it better to run on a treadmill than outside?

Because we now know that running outside and running on the treadmill are basically the same at a 1% grade, we can identify the specific workouts or instances when running on a treadmill might actually be better than running outside.

When the weather and footing are bad

This is the most obvious benefit of treadmill running, but it’s important to include because elements effect every runner differently.

Personally, I have a very difficult time when it’s hot or there is bad footing; however, put me on a clear road on a cold or rainy day and I’m a machine.

You may be the opposite, so don’t be afraid to hit the treadmill on the days you need to.

Getting in a good workout on the treadmill is better than suffering through a bad run or getting hurt and we went into this in further detail on our post about why you need to run on a treadmill sometimes.

Simulating race courses while indoors

One of the unique benefits of a treadmill is the ability to simulate your goal race course.

Many of the more advanced treadmills allow you create your own unique course profile, which you can use to simulate the exact course you’re training for.

Just program the machine, or if you don’t have that option, manually adjust the incline levels based on the course map, and you can train on the course any day of the week.

For runners training for the Boston marathon, you can even put lifts under the back end of the treadmill to simulate downhill running.

This trick is something I learned while running as part of the Hansons Olympic Development project.

You can now simulate the pounding of the downhills on your quads and be better prepared for the opening miles on race day.

Fluid and carbohydrate intake

As I’ve discussed many times, it’s critical that you practice taking in fluids and carbohydrates while following a marathon training schedule on your runs to teach yourself how to eat and drink without stopping.

Obviously, this can be a logistical nightmare if you don’t plan on carrying your water or gels with you.

Running a tempo run or long run on the treadmill will allow you to practice eating and drinking without slowing down.

While the treadmill won’t make the actual act of eating or drinking any easier, it can make it logistically possible.

When is it better to run on a treadmill than outside?

While running on the treadmill can have some unique advantages, it can also be detrimental to your long-term development if the only time you run outside is to race.

Here are some specific areas you need to watch out for if you’re a habitual treadmill runner:

You don’t learn how to pace on a treadmill

When running on a treadmill, it’s easy to “set it and forget it” and just lock into a target pace. Unfortunately, this method doesn’t teach you how to properly find and maintain pace on your own. As a consequence, you stunt the development of your internal effort and pacing instincts.

On race day, when executing race splits is critical, you won’t have developed that fine sense of pacing that is crucial to running a negative split and finishing strong.

Remember, we found lots of interesting statistics about why negative splits are better for runners chasing a PR.

The treadmill is boring

For the majority of runners, running on the treadmill is boring.

Without scenery passing you by and something to take your mind off the blinking lights in front of you, it’s too easy to look at the clock every 30 seconds and get discouraged that more time hasn’t passed since your last glance.

Likewise, when you’re running a tough workout outside, you can “feel” the finish line getting closer and you have a more natural sense of the distance remaining.

On a treadmill, your mind can’t visualize the finish line, so it becomes harder to concentrate when the pace gets hard and you need to push yourself.

In my opinion, you should approach running on a treadmill like you should with everything in life – in moderation.

What’s the bottom line?

The treadmill can be a great training tool and essential for those of us who live in harsh weather environments (both hot and cold).

However, don’t neglect the specific skills you need to develop by running outside on occasion.

Do you have any good tips for killing the boredom on a treadmill or unique ways you’ve implemented treadmill training? Let us know in the comments section, we would love to hear your story.