Treadmill running is not the first choice for many runners but provides some unique benefits and is a good alternative when running outside is not an option.
In many parts of the country the weather is turning colder (especially in the Northwoods of Wisconsin) and that treadmill in the corner is starting to look more enticing than it did a few months ago.
What's The Difference
The question I often get from patients is: What is the difference between running on a treadmill versus outside? There are surprisingly quite a few differences and some factors worth considering before you plan your next run. Before we dig into the differences let’s address the basic concerns many have.
1) Will running on a treadmill will change my form?
2) Is running on a treadmill easier because the belt is doing all the work?
Effects on Running Form
Running on a treadmill will not negatively impact your form. In fact, it can be used as a tool to improve your form.
A study looked at the variances in the kinetics and kinematics (basically every fine detail of how you run) and determined that treadmill running can be generalized to overground running.
This is important. Not only to you as a runner but also to all the research and run analysis that are being performed. I perform a run analysis on all my patients who, when recovering from an injury, want to return to running. I would be doing them a great injustice if what I observed was not generalizable to them running outside.
Improve Your Form on the Treadmill
Not only is your form not compromised, you can often focus on your form better when you are on a treadmill.
Think about it. You have total control over your speed, incline, and conditions.
If you are wanting to work on running a quicker mile, set the treadmill to the pace you are shooting for and get used to what it feels like running at that speed.
If you want to do hill work but live in Kansas, set the incline so that you can work on hill running.
If you want to work on your cadence, a treadmill is great for that and counting your steps per minute is much easier when you are not thinking about the sidewalk, dogs, or intersections.
Treadmill Running Has to Be Easier...Right?
The other thing I hear far too often is running on a treadmill is easier because the belt is doing all the work for you. Let's bury this myth once and for all.
There are multiple papers available which look at everything from VO2 max to heart rate to blood lactate threshold - all indicators of how hard you are working. The result of these research articles show that the efforts on a treadmill versus running outside are statistically very similar.
There are some minor changes for some runners, mainly influenced by how fast you run and if you are running at submaximal or maximal effort. But for the majority of runners there is no difference. I encourage you to read this 2019 systematic review if you want more details.
But I Need to Incline the Treadmill Still...Right?
You may have also read or heard that in order for your efforts on a treadmill to be the same as running outside you need to set the incline to 1%.
This is true, if you run a 7:09 minute mile or faster. Why such a specific number? Because of this article.
They looked at five specific speeds and inclines ranging from 0-5%. The result is that once you start running faster you have to elevate the treadmill slightly to offset the fact that you are not competing with wind resistance.
So, depending on your preferred running speed it may be beneficial to set the treadmill at 1%, especially if you are generally a faster runner.
The Beauty of Running is it Takes No Equipment
While there are some advantages to running on a treadmill, many of us (me included) prefer to run outside.
One of the great things about running is that you can do it anywhere. Throw on a good pair of running shoes and the whole world becomes your gym. No additional equipment needed.
So what are the advantages to running outside?
Training for a Race
Many of us run to prepare for a race. Either to test ourselves or just to stay motivated.
If you are training for a race you will be better prepared if you are running in the conditions that best simulate the race itself.
If you run on a treadmill every time it is cold and raining you may not be prepared for the day of the race. Conversely, if every time it is 90 degrees outside with 100% humidity you stay in the air conditioned gym you will suffer on race day.
Training for the conditions you will race in has a lot of value.
Benefits of Running Outside
Even if you do not run to train for a race there are several advantages to being outside.
Just being outdoors is healthy for all of us and something many city dwellers do not get enough of. I am lucky to live in the Northwoods of Wisconsin with easy access to nature and plenty of outdoor space.
Running outdoors also provides natural variability in surfaces, inclines, and directions.
It is a great idea to change your running surfaces both for injury prevention and to improve your small stabilizing muscles. Changing from grass to concrete to trail to track surfaces all provide you different experiences and different benefits.
Variability in inclines is also one of the great things about being outside. You can simulate many things on a treadmill, but running downhill is not one of them (outside of very expensive treadmills mostly used for research).
Finally, running on a treadmill is completely linear and straight forward while running outside has more variations.
Whether it is running the curves on a track, jumping over puddles on the road, or navigating roots and rocks on the trail. Variability in your running improves your strength and stability which may help reduce your rate of injury (especially if coupled strengthening exercises).
Dig Into the Research Yourself
If you want to know more about the physiological differences and commonalities between treadmill versus outside running I encourage you to look into the research. With that said, based on the systematic review of 34 research articles, the variations for the vast majority of you reading this does not matter. Consider the other variations discussed and rest assured that you are still getting a productive and quality workout in either setting.