Surge inaccurate when running on a treadmill

[runrd32]

Has anyone else found that when you are on the treadmill the surge is accurate to a point (maybe 8 minute pace) but as you increase your pace the mileage varies significantly from the treadmill mileage which I am guessing is accurate....

[Julia_G]

Hi, @runrd32, do you hold on to the sides when running on the treadmill?  That will definitely affect accuracy as all wrist worn trackers depend on vibrations from your steps transferred along your body and t your arms.  If you hold on, some of the vibration energy is absorbed by the treadmill, so not detected as steps.

[runrd32]

I don't but that would make sense. On the road/trails it is accurate but I
have tried it 3 times now on the treadmill. As I mentioned, at a slower
pace the surge actually is ahead on mileage but at increased pace it falls
behind.

[sshep19]

I have found the exact opposite the last three times I have run on the treadmill.  The surge is signifcantly behind the mileage, pace, distance shown on the treadmill.  I am not holding the sides when I run.  I have not found that pace makes any difference as the surge has been behind, regardless of how fast or how slow I am going.  Any suggested fix to that?

[shipo]

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@runrd32 wrote:

Has anyone else found that when you are on the treadmill the surge is accurate to a point (maybe 8 minute pace) but as you increase your pace the mileage varies significantly from the treadmill mileage which I am guessing is accurate....

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What you're missing is the whole "Stride Length" setting for treadmill running; if you set it for say, an 8:00 pace, and then you run a 9:00 pace, the Surge (or any other wrist based tracker) will over report your distance; conversely, if you run a 7:00 pace then the Surge will under report the distance.  Why?  As you speed up your stride length increases.

Case in point, using the Surge's in-built GPS, I get pretty accurate stats regarding distance and steps, and given I've had a Surge for 20 months, I have a lot of data available to make comparisons vis-à-vis pace and stride length.  Consider the following:

• Run 1: 16-Dec-2016 -- 10.15 miles -- 96:41 total time -- 9:31 pace -- 16,087 steps -- 39.98" stride
• Run 2: 9-Nov-2016 -- 10.15 miles -- 86:47 total time -- 8:34 pace -- 14,656 steps -- 43.88" stride
• Run 3: 16-Sep-2016 -- 10.94 miles -- 82:07 total time -- 7:31 pace -- 14,153 steps -- 48.98" stride

Note 1: The two 10.15 mile runs were done during my normal lunchtime run around a lake near my office; the 10.94 mile run was my first leg of a long 200 mile/12-person relay so it was a sort of a race type of event (but I had to save enough for two other legs so it wasn't all-out).

Note 2: As you can see by the above stats, my stride length has a delta of exactly nine inches over those three runs; I have other runs (such as recovery runs the day after a race) where my stride length is even shorter (like 36.5").