Is the Treadmill or My Watch More Accurate?
You’ve just plugged away for an hour on the treadmill with a great run and when you finish there’s the distance shown on the treadmill and the distance on your running watch. Which should you use?
This could be the shortest article I’ve ever written, but let’s talk a bit more about how to calibrate your watch and why the treadmill will always be the more accurate of the two.
Do running watches work on the treadmill?
Yes and not really.
Every fitness tracker and GPS running watch has an indoor running mode, which would make you think it’s going to correctly correlate your data from the treadmill.
Your GPS watch is designed to utilize satellites to track your movements. On the treadmill that GPS is turned off and it’s trying to use the internal accelerometer to measure arm swing and bounce to guesstimate your pace.
You can improve the readings a few ways:
- When setting up your watch, do the stride length test on the treadmill.
- Opt for a watch like the Garmin Forerunner or Coros Pace which has a calibrate treadmill feature
- Try using a foot pod (though tests I’ve seen say it’s as accurate as a calibrated watch)
- Turn off the autolap feature and hit lap yourself with each mile if you want the most accurate splits saved to your watch or when you sync to Strava.
How does the Garmin Calibrate Treadmill feature work?
Having used multiple Garmin watches I can say it’s better some days than others, but never truly accurate.
- After finishing an Indoor Run workout, when you go to save it will ask you to calibrate.
- Then you update the distance on the watch to match the distance shown on the treadmill screen.
- It will save this data and try over time to make your treadmill runs more accurate.
At minimum you’re able to update the distance, which means you’ll have the correct data in your files for how far you ran and the total time.
This feature is not available on many other watches, including my favorite Polar Vantage V2 (really the only drawback of that watch).
And to be clear here…the treadmill is still the owner of the accurate distance, not your watch.
Is my Apple Watch or the Treadmill Right?
Apple watch indoor run accuracy falls directly in line with all of the notes above about other GPS running watches and will be the same for any tracker like FitBit.
What if my watch says more than the treadmill?
The treadmill is still right.
What if my watch says less than the treadmill?
The treadmill is still right.
Will a foot pod be more accurate on the treadmill than my watch?
If your foot pod is used to you running outside then it’s measured your stride length that way, which will change some on the treadmill.
You can calibrate your footpod on the treadmill and you may find this is more accurate than your watch, especially if your watch is not one that allows you to calibrate.
Calibrating the footpod is about the initial set up of recording stride length information. While for most watches we are referring to updating the data after your run to match the treadmill.
While training in Miami years ago and doing more indoor biking, I had the Garmin foot pod connected to my bike and it really isn’t that noticeable. It’s secured tightly and after a workout or two, you won’t think about it being there.
How do you know if your treadmill is accurate?
Now this is a good question to ask.
You may have noticed that treadmills can feel different from one another. This could be due to a treadmill needing to be calibrated or simply the setting. Usage is the big factor in a treadmill losing calibration (or in my case being moved repeatedly!).
Calibrating the Incline
First is calibrating the incline to ensure you aren’t adding resistance or not getting enough.
- On the set up page of most machines is a “calibrate” button, which will run through various inclines to try and get it reset.
- Place a level on your treadmill and make sure front to back and side to side are level. We found after my last move that mine was no longer correct and 1% is now 0.
Calibrating Treadmill Speed
Calibrating the speed of your treadmill is a much more complicated process.
- Find the length of the treadmill belt in CM
- Make a white mark in chalk on the end of the belt
- Turn the treadmill on to a speed you want to check
- Turn on a timer and count up to 30 times where the chalk mark passes you
- Time to calculate
Treadmill speed is distance / time. Divide the distance (belt length x number of revolutions) by the time measured. For example, if the belt length was 3 meters, and it took 20 seconds for it to do 15 revolutions, then the speed is (3 x 15) / 20 = 2.25 meters/second (or 8.1 km/hr or 5 mph).
If the treadmill is off you’ll need a repair person to try and calibrate it or you can mentally make adjustments to what you know the speed to be.
More treadmill running questions answered:
- Why do I run slower on a treadmill?
- Best At Home Treadmill for Running
- How to survive long runs on the treadmill?
- Speed workout ideas for the treadmill
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