Side-by-side walking with different results

[public_acct13]

I have a Charge3 (actually new, taken out of the box only about 2 months ago). My husband has a Charge5. 

We walk together. His stride length  is 29.4, mine is 26 (defaults).

As expected, we have the same duration, and (based on differing stride lengths) different step counts.
However, we have very different traced results for distance and pace. WTF???

TiA

	Charge3	Charge5
Day1 distance	1.39 miles	1.48 miles
Day1 pace	18.55	17.24
Day1 minutes	26	26
Day1 steps	3209	2961
Day2 distance	2.17	2.37
Day2 pace	19.16	17.34
Day2 minutes	42	42
Day2 steps	5123	4779

[Odyssey13]

Hi @public_acct13  as these are wrist based devices, we do need to swing our arms to have the steps counted. I tend to put my hand in my pocket or hold something in it, so my steps aren't all counted. Might this be the case with you while walking? Love seeing a couple walking together!

[public_acct13]

Nope, this speculation is not supported by the math. SUPPOSING that each arm swing is a step, please note the differing step counts in the table, above. Also note the different stride lengths. There are 63360 inches in a mile. Based on these numbers...

Me: 3209 steps TIMES 26 inch stride = 83434 inches DIVIDED BY 63360 = 1.32 miles
Him: 2961 x 29.4 = 87053.4 / 63360 = 1.37

So the pure math, equating an arm swing with a step, doesn't compute accurately with the numbers reported in the app.

[LZeeW]

@public_acct13   I apologize if I am misreading your post.  You mention the "tracked" distance.  Is this the GPS tracked distance?  Meaning that the pace times you list are from the GPS calculation?  Two people who cover the same distance in the same amount of time are moving at the same pace.  Why is there a difference?

• GPS accuracy isn't pinpoint.  GPS.gov gives smartphone accuracy as a 16 ft radius in open sky.
• If your husband's Charge 5 was using built in GPS, there is no published data on its accuracy.
• Fitbit's GPS tracking maps don't put you "back on the road" like your car's GPS does.  I have maps that show me walking through walls.
• I've walked side by side with my husband where I use a Versa 3 and he wears a Sense (both with built in GPS) and the maps have us on different sides of the street.

All of your differences are close and look like they are well within known GPS accuracy information.

[public_acct13]

Thanks! You restated my question far better than I actually asked it. 🙂 

I do not use GPS with my Charge 3, but yes, we've seen exactly some of the amusing routes recorded on the Charge 5. Hmmm, why did my husband cross the road? hahaha

But seriously, what we are looking at is the exercise reported in the app itself, trying to understand how these numbers are being tracked/calculated so that we can understand why the two of us, walking side by side, have different reports, and consistently different over multiple walks. 

I appreciate your insights -- thank you!

[LZeeW]

@public_acct13    I can give you some additional information, since you clarified that you weren't using GPS.

• Your Charge 3 distance is a steps x stride length distance.  I suspect you and your husband kept a nice constant speed.  But an individual, walking alone, will change their stride length at different speeds.  It will also change going up and down steep hills.
• The Charge 5 GPS distance is the mapped GPS distance.  It will have the errors of you walking through your neighbor's yard and so on.

Trying to compare your two walks is really trying to compare apples and oranges.

In addition to walking through walls, my GPS maps said that I walked off a cliff one time and levitated above a 100 ft ravine another time.