You start your run on the treadmill and set it to your normal outdoor pace. However, you notice the pace feels different than outdoors. You may start to wonder: is something wrong with your fitness? (No.) Is the treadmill calibration off or does running on the treadmill feel than different from outdoors? Many runners are familiar with this exact scenario. This article will answer all your questions about treadmill pacing, including if treadmill running is different, if you should use a 1% incline, and how to pace on the treadmill. At the end of this article, you will find a treadmill pace chart. This treadmill pace chart will aid in converting miles per hour (mph), which is the number used on the treadmill, to minutes per mile.
Is Treadmill Running Different than Outdoor Running?
Running on the treadmill is still running. However, the nature of treadmill running (the belt pulling behind you) can cause some alterations to running form. The variations and their significance may differ depending on how familiar you are with the treadmill and your own individual gait.
A 2017 study in the International Journal of Exercise Science concluded that stride length changes in relation to speed are different on the treadmill than outdoors. On the treadmill, runners tend to linearly increase their stride length as velocity increases. When the same athletes run outdoors, stride length eventually plateaus even as velocity increases.
The treadmill is an amazing tool, especially in winter or for a time-crunched runner. None of these differences mean that treadmill running is a poor choice. Rather, these differences simply mean you should know that paces on the treadmill may differ from paces outdoors.
Do You Need a 1% Incline for Accurate Pace?
While the 1% rule for the treadmill had a sound basis in research at its conception, we now know it’s not a universal rule. In fact, a 2019 systematic review in Sports Medicine found that a 1% incline only makes a significant difference at velocities of 13 km/hr (8 mph) or faster. Some reviewed studies even found that a 1% incline created a greater oxygen demand, not an equivalent one, to outdoor running. At some paces, 0% on the treadmill will have lower oxygen demand than outdoors, but 1% will have higher oxygen demand than outdoors.
Additionally, a 1% incline for an entire treadmill run may increase the risk of overuse injury. I generally encourage athletes to vary the incline throughout the run. By changing the incline every few minutes, biomechanics such as the angle of the foot strike are slightly changed; this reduces the risk of overuse injury. Incline variations also mimic outdoor running, as most runners encounter even slight terrain changes in their runs.
How Should I Adjust the Pace on the Treadmill for Incline?
A 2022 study in Biology examined outdoor and treadmill running at flats and inclines using twenty recreational runners. From the data, the researchers concluded that the variables predicting inclined treadmill performance did not predict level treadmill performance, and vice versa. Various factors affect a runner’s uphill velocity.
Rather than relying on a pace chart that attempts to convert graded paces to flat ground paces, pay attention to your effort. Make adjustments to the pace that feel appropriate to you.
If fast paces make you feel like you will fly off the back of a treadmill, you can use similar efforts at a higher gradient. For example, doing a tempo run at a 4% incline (paced by effort) may feel more secure than a tempo run by effort at 0%.
Why Do Treadmill Paces Feel Different than Outdoors?
Unless you deliberately set up multiple fans, treadmills are often in locations that have less circulating air than you would outdoors. As a result, many runners experience the sensation of heating up on the treadmill. In coaching hundreds of runners, I have often observed multiple runners report that they run slower on the treadmill if the heat in the house is on or they do not have fans set up.
In support of this observation, the above-cited 2019 review found that faster submaximal speeds resulted in higher heart rate and RPE on the treadmill than outdoors. Because of that observed elevation of RPE and heart rate, the same pace likely feels a bit harder outdoors than on the treadmill.
When running on the treadmill, set your pace based on the rate of perceived exertion or heart rate (depending on which you personally use to gauge training intensity). Do not force the pace you normally run outside if the effort feels harder than prescribed. This recommendation applies to both easy runs and hard workouts.
Is My Treadmill or My Watch Correct on Pace?
When running on the treadmill, use the treadmill for pace and distance, not your GPS watch. You can still use your watch to record the distance and pace, but know that it may not be highly accurate.
This article here on the website delves into why your GPS watch may not accurately estimate pace when you are running on the treadmill. In summary, your GPS watch uses an accelerometer to estimate indoor training paces. However, on the treadmill, many runners slightly differ in their gait (especially arm swing). Your GPS watch may be closer to the actual pace or have a large margin of error based on your individual gait.
Possibly, neither are accurate. Some commercial treadmills end up poorly calibrated without appropriate maintenance. Their readout may not be accurate and neither will your watch. In that scenario, focus on your rate of perceived exertion and training time. In the grand scheme of things, 6.0 vs 6.5 miles will not make a significant difference.
Treadmill Pace Chart
In the MPH (miles per hour) column, you see how the pace is presented on the treadmill. (6.0 on the treadmill is 6.0 mph if you are in the US.) In the right column, you see how the mph pace convert to minutes per mile (which is how most GPS watches report pace).
The kilometer treadmill pace chart can be used the same way. KPH (kilometers per hour) is how pace is represented on the treadmill; min/km is how most runners think about their pace outdoors.
As you would with outdoor running, avoid hyper-focusing on pace when running on the treadmill. Know how to make the appropriate adjustments and set the machine for your needs that day. Your worth is more than your pace, including on the treadmill!