Doug Eldred

Q: Manual (stride) calibration needed

As directed, I calibrated my Apple Watch with an outdoor walk of 20 minutes.  That was apparently at about 3.1 mph.  When I use an indoor treadmill, it appears to think that every walk has the same stride length.  It's not easy or maybe even possible for me to calibrate EVERY speed outdoors - especially because the Workout app doesn't even SHOW speed directly - so there needs to be some way of telling the Workout app "the last workout was at 2 mph, for 30 minutes, so I went exactly 1 mile - recalibrate the stride length for 2 mph accordingly".  PLEASE!

Apple Watch Sport 38mm, iOS 9.2, null

Posted on Feb 24, 2016 9:28 AM

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Q: Manual (stride) calibration needed

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  • by Meg St._Clair,Helpful

    Meg St._Clair Meg St._Clair Feb 24, 2016 9:39 AM in response to Doug Eldred
    Level 9 (58,855 points)
    iPhone
    Feb 24, 2016 9:39 AM in response to Doug Eldred

    Submit your feedback to Apple here:

     

    http://www.apple.com/feedback

  • by Jonathan UK,

    Jonathan UK Jonathan UK Feb 24, 2016 9:42 AM in response to Doug Eldred
    Level 7 (33,944 points)
    Apple Watch
    Feb 24, 2016 9:42 AM in response to Doug Eldred

    Hi Doug

     

    In order to improve the accuracy of estimations from the Workout app, calibrate your watch at each of the speeds at which you typically walk, jog and/or run. At all times, allow the arm on which you are wearing your watch to swing naturally during your workout.

     

    It is not necessary to complete 20 continuous minutes at each speed. If preferred / necessary, you can instead complete 20 minutes at each speed spread over the course of multiple outdoor Workout sessions.

     

    More information:

    Calibrating your Apple Watch for improved Workout and Activity accuracy - Apple Support

  • by Chris J Davies,

    Chris J Davies Chris J Davies Mar 5, 2016 2:17 AM in response to Doug Eldred
    Level 2 (198 points)
    Apple Watch
    Mar 5, 2016 2:17 AM in response to Doug Eldred

    it is a pity that there is no way of manually editing the distance after an indoor treadmill session. After all, the distance should be known to a pretty high degree of accuracy. However, I wonder if that would affect the estimate of calories used. Does the Apple Watch calculate calories used with reference to just the heart rate and time or does it include distance as well? I have always wondered this with my fitbit HR.

  • by Meg St._Clair,

    Meg St._Clair Meg St._Clair Mar 5, 2016 8:06 AM in response to Chris J Davies
    Level 9 (58,855 points)
    iPhone
    Mar 5, 2016 8:06 AM in response to Chris J Davies

    Chris J Davies wrote:

     

    it is a pity that there is no way of manually editing the distance after an indoor treadmill session.

    I agree, it would be a nice feature. Nike+ Running does (or did) allow you to do that. As does, I believe, Polar Flow.

     

    Submit your feedback to Apple requesting such a feature here:

     

    http://www.apple.com/feedback

     

    Of course, this does assume that the treadmill is accurate. I know that the calorie estimate on gym equipment is notoriously inaccurate. I don't know about the distance.

     

    Sorry, don't have the answer to your other question.

  • by Lawrence Finch,

    Lawrence Finch Lawrence Finch Mar 5, 2016 8:24 AM in response to Meg St._Clair
    Level 8 (37,982 points)
    Mac OS X
    Mar 5, 2016 8:24 AM in response to Meg St._Clair

    Meg St._Clair wrote:

     

    Of course, this does assume that the treadmill is accurate. I know that the calorie estimate on gym equipment is notoriously inaccurate. I don't know about the distance.

     

    I've compared my  watch, my Fitbit zip and the distance shown on the treadmill. They aren't close. Given that I've calibrated the zip, I trust it. The watch shows about 1/2 of the zip distance, and different treadmills are different from each other and from the zip.

     

    However, distance is irrelevant. From an exercise perspective distance is not as important as number of steps. And the watch is way off on that also.

  • by Doug Eldred,

    Doug Eldred Doug Eldred Mar 5, 2016 8:28 AM in response to Lawrence Finch
    Level 4 (3,271 points)
    Mar 5, 2016 8:28 AM in response to Lawrence Finch

    If you're only seeing 1/2 the correct distance, are you swinging your arms as you walk on the treadmill?  At least the watch arm needs to be moving for it to correctly identify steps.  My experience is similar to yours if I do NOT swing my arms, but roughly right if I do.

  • by Meg St._Clair,

    Meg St._Clair Meg St._Clair Mar 5, 2016 8:54 AM in response to Lawrence Finch
    Level 9 (58,855 points)
    iPhone
    Mar 5, 2016 8:54 AM in response to Lawrence Finch

    Lawrence Finch wrote:

     

     

    However, distance is irrelevant. From an exercise perspective distance is not as important as number of steps.

    I'm not entirely sure I understand that. Why are steps more important than distance?  My reading seems to indicate that time spend active and, to a slightly lesser extent, effort, are what's important for fitness.

  • by Chris J Davies,

    Chris J Davies Chris J Davies Mar 5, 2016 9:04 AM in response to Meg St._Clair
    Level 2 (198 points)
    Apple Watch
    Mar 5, 2016 9:04 AM in response to Meg St._Clair

    I would guess that steps are more important because of varying stride length. It's the motion of moving your muscles to move the legs that uses energy rather than your stride length. Plus intensity level as well.

  • by Meg St._Clair,

    Meg St._Clair Meg St._Clair Mar 5, 2016 9:21 AM in response to Chris J Davies
    Level 9 (58,855 points)
    iPhone
    Mar 5, 2016 9:21 AM in response to Chris J Davies

    Chris J Davies wrote:

     

    I would guess that steps are more important because of varying stride length. It's the motion of moving your muscles to move the legs that uses energy rather than your stride length. Plus intensity level as well.

    That still doesn't make much sense to me. If I run a mile, I will probably take fewer steps than if I walked a mile as strides lengthen. But I would have used more energy running. If I walk a mile using very tiny steps, will I have gotten more exercise than If I walk that same mile use normal steps?

     

    I'm not trying to say you (or Larry) are wrong, not trying to be argumentative. Just trying to understand.

  • by julie78787,

    julie78787 julie78787 Mar 6, 2016 6:04 AM in response to Chris J Davies
    Level 1 (20 points)
    Apple Watch
    Mar 6, 2016 6:04 AM in response to Chris J Davies
    it is a pity that there is no way of manually editing the distance after an indoor treadmill session. After all, the distance should be known to a pretty high degree of accuracy. However, I wonder if that would affect the estimate of calories used. Does the Apple Watch calculate calories used with reference to just the heart rate and time or does it include distance as well? I have always wondered this with my fitbit HR.

    As nearly as I can tell, and based on feedback from Apple, "active calories" are determined based on heart rate, weight and percentage body fat. Those need to be entered on the "Vitals" screen

     

    I'm in the same situation with you - my "steps per minute" on a treadmill are fairly constant and I lengthen my stride at higher speeds, which is probably a habit from when I spent more time on a 10-speed racer (okay, it was anywhere from 10 to 21 gears ...) where I could pick a different gear to keep the same number of RPMs.

     

    If you want an accurate measure of distance, get a stride sensor, such as one from Polar, and use Polar Beats along with the Workout app. The Watch measures strides by looking for regular changes in accelerometer readings. From those measurements it infers -- indirectly -- that you've made a single step. A stride sensor attached to your shoe, like the ones from Polar, can more directly measure the actual distance since the equation for distance is d = 1/2 a t^2 (there will be a quiz later ). I've used Polar Beats and Endomondo together with the Workout app and they work fairly well together. Just keep in mind that a stride sensor is going to be far more accurate than what the Watch can tell you since it is measuring actual distances. Also remember the old adage "A man with one clock always knows the time. A man with two is never certain." -- different apps may calculate values differently.


    Without accurate foot acceleration measurements, the Watch is guessing based on the calibration which was done, and as you've found your stride length (and mine ...) changes with speed.

  • by Chris J Davies,

    Chris J Davies Chris J Davies Mar 6, 2016 10:52 AM in response to julie78787
    Level 2 (198 points)
    Apple Watch
    Mar 6, 2016 10:52 AM in response to julie78787

    Overall, I am not too worried if my distance is not so accurate, as long as the calories are (well, as accurate as they can be with any kind of measurement like this).

  • by julie78787,

    julie78787 julie78787 Mar 6, 2016 12:22 PM in response to Chris J Davies
    Level 1 (20 points)
    Apple Watch
    Mar 6, 2016 12:22 PM in response to Chris J Davies
    Overall, I am not too worried if my distance is not so accurate, as long as the calories are (well, as accurate as they can be with any kind of measurement like this).

    In that case, a trip to the gym (if you belong to one) may be in order. Most gyms can tell you your body fat percentage. Also, keeping your weight updated, unless you maintain a fairly consistent weight. Those two values are what gets fed, along with your heart rate, into the active calories model.

     

    One thing I learned, with a bit of confirmation from Winston Churchill (heh) is that your warm-up calories will be lower, even if you are doing a constant amount of "work" throughout your walk. This is because it takes your heart a while to respond to exertion. So, either cool-down from your exercise, or let the workout continue a bit while your heart rate returns to normal. I started doing this for short workouts - 30 minutes or so - and it greatly improved the accuracy compared to weight, distance and time models.

  • by julie78787,

    julie78787 julie78787 Mar 6, 2016 12:28 PM in response to Meg St._Clair
    Level 1 (20 points)
    Apple Watch
    Mar 6, 2016 12:28 PM in response to Meg St._Clair
    That still doesn't make much sense to me. If I run a mile, I will probably take fewer steps than if I walked a mile as strides lengthen. But I would have used more energy running. If I walk a mile using very tiny steps, will I have gotten more exercise than If I walk that same mile use normal steps? I'm not trying to say you (or Larry) are wrong, not trying to be argumentative. Just trying to understand.

    The estimated stride length is only used when you're not paired to your iPhone, which is what provides the GPS signals that is used to compute distance. If you left your phone at home, and you used a much shorter stride, you should get credit for a longer walk or run. How many calories that would wind up being would be determined by your heart rate.

  • by Doug Eldred,

    Doug Eldred Doug Eldred Mar 8, 2016 10:54 AM in response to Doug Eldred
    Level 4 (3,271 points)
    Mar 8, 2016 10:54 AM in response to Doug Eldred

    Interestingly, it seems that over time the accuracy is improving, doing only indoor treadmill walks, both at home (low-end treadmill) and using professional equipment.  I have NOT done any new outdoor calibrations (yet), but intend to do so when the weather is a little more cooperative.  It now seems to be about 3-5% high at at least two treadmill speed settings.

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