Tennis, bad couting distance?

Indoor distance tracking works on the assumption that your wrist's movement is rhythmic and regular - like for example during treadmill running. There is no easy way to track distance accurately for activities where there are frequent and rapid changes of speed and direction with a wrist-worn device based on nothing more than cheap accelerometers. A gyroscope wouldn't help either.

As TeaRacer wrote, the watch counted 3500 steps, and still the distance was close to zero. At other indoor activities, the average stride length is used for estimating the distance, but it looks like it is not the case at tennis. Perhaps at other indoor activities too, I did not test all of them. The question is rather whether it is intentionally disabled, a problem with some settings, or a bug.

Personally, I'd tell it is probably intentional, because you log plenty of false steps just by swinging the racket when playing tennis, so I think the steps are not used for the calculation. On the other hand, if Garmin disabled the distance estimation due to false step counts, it is surprising they did not turn off the pedometer completely, like they do for example at cycling.

Additionally, if they disabled the steps for the distance calculation intentionally, I would expect a zero distance, and not 60m. TeaRacer told me already earlier that his other indoor activities calculate the distance correctly, so a wrong value in the average stride is not the culprit.

I'd advise reporting it to Garmin as a bug. Probably best to the beta team, since I do not think the standard support would do anything about it.

Yes, that's exactly how Garmin Vivoactiv measured it accurately, even volleyball, football, tennis and badminton. For Instinct 2 and earlier versions, it doesn't matter if it's a treadmill activity, an indoor run. That's why I was looking forward to the tennis activity being different. Unfortunately it's not. Of course, if I leave the watch off during the same activity, it measures the steps in exactly the same way. I think it's a gyroscope, I can't believe there was a bug in Instinct Solar, Instinct Solar and now Instinct Solar 2.

TeaRacer said:

That's why I was looking forward to the tennis activity being different. Unfortunately it's not.

Hold on, previously you wrote me, at the Treadmill and Indoor Run activities it counts the distance correctly. So does it or does it not? If you get no distance anywhere indoors, then first of all verify the setting of the Stride Length, and then try calibrating the treadmill activity.

Edit: I do not find the setting for the custom stride length at Instinct 2, as it was at Instinct, so just do the treadmill calibration, and also make sure you already logged some outdoor GPS walk or run activities.

TeaRacer said:

For treadmill and jogging indoor track, that's OK.

In that case, why don't you use one of these, for the custom activity?

I've already written that, if I use a treadmill or indoor running, they don't work for activities like tennis, badminton, volleyball. They do not show distance. But when running on a belt and an oval, yes. That's why I said that the absence of a gyroscope may be to blame, as there is a frequent change of direction in these sports.

TeaRacer said:

I've already written that, if I use a treadmill or indoor running, they don't work for activities like tennis, badminton, volleyball.

OK, I do not think you told it, but I finally understand now.

TeaRacer said:

That's why I said that the absence of a gyroscope may be to blame

That makes no sense to me. Without the gyroscope the watch has no orientation in space, and has less capability to detect changes of direction, not more. Anyway, AFAIK only steps sensed by the accelerometer are being used for the distance calculation, so on my mind there is something else going on.

Please share links to two tennis sessions - one recorded as tennis, and the other one recorded as treadmill. And then also one true treadmill activity (recorded with the same activity profile as the tennis session). Preferably all from the same day. The sessions may be quite short, just couple of minutes. I'll look at the data - perhaps I'll see where the problem comes from.

So, I added Tennis to my watch too, and simulated a brief indoor activity with it, randomly running in diverse directions, and swinging my arm wildly. I generated around 300 steps, and the distance shown was 0.27 km, which is perfectly fitting the distance I would get when using the Treadmill activity with the same amount of steps.

So I would tell that in your case there is a problem with the stride length calibration. In your place, I would try going to a stadium track, start the Treadmill activity (neither Track nor Run !), and run until the watch shows minimally 1500m or 1 mile. Best done on the lane 1, and completing the full round, so that you can easily calculate the true distance you did. When you then stop the activity, before you save it, scroll down and select Calibrate & Save. It is also described in the manual here: https://www8.garmin.com/manuals/webhelp/GUID-31D23DBB-57C2-4DF7-A0C9-8D1A00AB4BE7/EN-US/GUID-86541696-B60E-44BC-9A46-4349C86A1CD8.html 

Of course, you could do it also on a treadmill, but it may not be well calibrated itself. Doing it on the track is definitely safer (and more fun anyway).

I can try, but I calibrated IS 1, IS Solar, and the problem was the same. I will try to calibrate IS 2 Solar as well, but I don't think there is a problem with the calibration. Try playing volleyball, football, badminton and you'll see. It just doesn't run here and there, it doesn't simulate real sport. If I run here and there, it will measure OK. Otherwise, after 1.5 hours of football, I had about 5,000 steps and the distance was also about 0.3 km. If it was whisperately calibrated, the difference plus a mine is 20%, but not that big.