Why does my Fitbit under report steps and distance when I walk briskly

[Auden]

I have a Fitbit Flex which seems relatively accurate when walking normally but when I am walking briskly ( around 4 mph) over known distances it under reports both my number of steps and distance by around 30%. Why? Is there anything I can do to correct it?

[Jim_M]

What are your arms doing during the walk?

What are your walking and running strides set to?  (at a certain speed, fitbit will start using your running stride, and that's somewhere around 4mph, I've heard)

[Dominique]

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@Auden wrote:

Is there anything I can do to correct it?

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It's as @Jim_M said, and the only way to fix it is to enter your brisk walking stride length in the field for your running stride. This means you will be "short-changed" (in terms of distances and calories) if/when you are running, unless you make the necessary change to your settings and sync with your tracker.

Note that the overestimation of your distances will also lead to an overestimation of calories burned and VAM's earned.

[kbh135psu]

I am having overestimation issues with my Force. I walked three steps between weight machines at the gym last night and it added 353 steps to my count. Any ideas why this is happening?

[HarleyBrat119]

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@kbh135psu wrote:

I am having overestimation issues with my Force. I walked three steps between weight machines at the gym last night and it added 353 steps to my count. Any ideas why this is happening?

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I am having the same issue with my Flex. I am mostly bedridden and bought the Flex as a last ditch effort to make myself move even when I feel I can't. I set my initial goal to 2000 steps a day. This morning, approximately 1 hour after waking, and before I had even left my bed, my Flex began vibrating. I synced and checked my dashboard and it said I had exceeded my goal with 2,478 steps. I have had so many of these issues since purchasing them for myself, my mother and my children. I thought syncing with my family nearby was issue so we all only sync when locked away in a room alone. My mother's recorded 347 steps when she walked approx. 30. I was so excited about this product and REALLY wanted it to work, but I am afraid it is time to send them back.

[slysam]

I have a One so it is worn on my torso--different than the Force. My One usually does okay with walking, I do pick up some "steps" strength training if the movements are big enough--i.e. step ups, lunges, etc. My guess is with the wrist worn Force, you might have picked up some "steps" lifting weights. I think this is fine, the fitbit's use an accelerometer and are tracking movement not really "steps" in the same way an old school pedometer does. I think the formula is translating movement into steps if big enough and meeting certain criteria. On my One, I've see a lightly active activity level for time where it didn't count any or many steps. Once it was doing a suspension training workout--no steps were taken or counted but the Fitbit credited me for activity (underestimated, but I was impressed) and the other time was cleaning a closet so lots of bending over and reaching up but few steps. I think the activity level and calorie burn will be underestimated though as the Fitbit's don't have a way to factor in resistance. Even if my One picks up movement strength training (my one only does for larger movements while strength training though), it never credits as much as my Heart rate monitor or the exercise database would for resistance training activities. Sometimes it even classifies a resistance workout as "sleep" if it doesn't pick up enough movement throughout the workout.

[slysam]

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@Auden wrote:

I have a Fitbit Flex which seems relatively accurate when walking normally but when I am walking briskly ( around 4 mph) over known distances it under reports both my number of steps and distance by around 30%. Why? Is there anything I can do to correct it?

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Auden, I have a One so it is different than the Flex. I find my One does better with brisk walking than slower walking. Though when I have tested it it is fine with just about any walking where I am traveling. I have done activities where it doesn't count all the steps--in my case usually dancing that involves soft, fluid movements where you isolate the impact to the legs (usually with bent knees). I think impact is a factor, as my fitbit does consistently credit higher for impact activities than non-impact. And it sometimes misses steps with non-impact or isolated impact movements. It could be your brisker walking is softer or more fluid--it is opposite for me though. So how to you know it is undercounting your steps with brisk walking? As far as the distance, the main thing is to calibrate your stride settings--both walking and running. If you don't run often (or at all) you may prefer to use your brisk walking as the "running stride". If you already calibrated, you set your stride too short. This is a common error, you want the average amount of distance you cover per footfall as your stride. Sometimes people measure their inseam, sometimes they count both right and left footfall as a stride, etc. The easiest way to calibrate (in my opinion after trying several methods) is to walk then run (or briskly walk) a measured, flat, known distance like a track. If your fitbit has a timer (all that sleep track do--using the same method) use it. Start the timer while standing still before your first step and stop it while still after the last step. There are a few different formulas (depending on whether you want metric or imperial measures) where you plug the distance covered and your fitbit counted steps to see your "average stride length".