Treadmill vs. Nike+

Does anyone know whether the treadmill or Nike+ is more accurate?

20131015-111935.jpgI ran on the treadmill at the gym yesterday and used my Nike+ chip as backup for tracking my time and distance.  Nike told me that I went .21 further than the treadmill did, with my average pace being 8:34 and my best mile being 8:24, while my treadmill mile was 10:26.

I ran until I hit a mile on the treadmill just to be sure that I actually completed the distance I wanted – if I went a little further, great. However, I am unsure which device is more accurate than the other. Because I am training for another 5k (and hopefully something bigger down the road), my times are important to me!


I’d like to think that Nike+ is more accurate (obviously I would LIKE that), not only because my mile is better but because my time is more in line with other runs I have done. The day before yesterday I ran outside using the chip and it told me that my pace was 8:48 per mile. I have also done other runs using MapMyRun and GPS, and the Nike times are closer to those than the treadmill is.

Now, I am POSITIVE that I was running faster yesterday (treadmill) than I was the day before (outside). This leads me to believe that between my Nike+ and MapMyRun data, the apps are more accurate than the treadmill. But how can I be sure?

Has anyone else experienced this, or have any insight as to which is more trustworthy? I understand that treadmills are calibrated to measure your speed and distance using the belt and that Nike uses the sensor to calculate your stride, but I don’t understand how there could be such a large difference. My brothers who are both runners have always told me that your time on foot will always be better than on a treadmill, but I wasn’t expecting this!

5 thoughts on “Treadmill vs. Nike+

  1. nolongernakedrunning

    I’m not familiar with Nike+ but do use a Garmin Footpod when on the treadmil as it’s more accurate than the treadmill itself. Are they similar? The reason a footpod would be more accurate is that it’s calibrated to your stride/cadence so it measures your actual speed and distance versus the treadmills speed and distance.
    The TM may be going at a 10min/mi pace which would give you 1 mile every 10 minutes. Your own cadence could be going faster or slower than this– meaning on a sidewalk you would be moving faster or slower than a 10min/mi pace. if you take small, quick steps on the belt many times you are moving faster than the belt, even though you are not ‘beating the belt’ It’s why sometimes effort feels different on a treadmill also– easier for some and harder for others. The only way to figure it out is to have a calibrated footpod (or foot sensor)
    I hope that makes some sense. Keep in mind the only way to have a truly accurate footpod is to calibrate it by running an even pace on a track.

    • katiefoley11

      Hi! I do think that Nike+ is similar to Garmin Footpod. I have a sensor that goes under the sockliner in my shoe that tracks my run and gives me the option to calibrate once finished. That makes sense about the treadmill and personal pace. I hadn’t realized that your cadence could a different speed than the treadmill despite the belt. Thanks for the input!

  2. Jesse - Questionably Texan

    I used a Nike+ for a few years when I first started running, and they are useful only as an estimate (unless you have the Nike+ with GPS, but that’s useless on a treadmill anyway!)

    The old style Nike+ sensors could be calibrated over a known distance, and I assume that the current ones can be calibrated too. Calibrating mine helped some with the accuracy, but if I ran a different pace than when I did my calibration run, the distance was off a greater amount.

    Treadmills aren’t necessarily 100% accurate, but they’re likely more accurate than the Nike+. It’s relatively easy for a treadmill manufacturer to program the distance/pace based on how fast the belt is turning because they know exactly how long the belt is, but it’s a lot harder to program a Nike+ device to be accurate because how far one step is for everybody differs, and it differs based on how fast the individual is running.

    Go out to a standard high school running track and see how your Nike+ compares. One loop (in the inside lane) is 400m, or 0.25 miles. I’d run four loops (~1 mile) and see what your Nike+ says. I bet you’ll be surprised how far off it is!

    If you don’t want to go through all of that trouble, then just train as if the treadmill is accurate. On race day, I’m sure you’d much rather find out that the treadmill was under-estimating your speed/distance. If you trust the Nike+ and it’s wrong, you’ll be disappointed when you find you’re having to run “farther” than what you thought.

    • katiefoley11

      Hello! I took your advice and used my Nike+ sensor on a track. Turns out that it was spot on! Thanks for the tip!
      And yes, I would much rather find out that the treadmill was under-estimating my speed and distance 😉
      Do you have experience with MapMyRun?

      • Jesse - Questionably Texan

        I’ll have to admit that I’m surprised that the Nike+ sensor was spot on. I assume that they’ve perfected the system since I used it (I used it when it was new to to the market).

        I’ve used MapMyRun a little, but not much. Since it’s GPS based, I’d consider it to be accurate (relatively speaking anyways). I normally run with a Garmin GPS watch to track my miles.

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