Announcement

Collapse
No announcement yet.

Novice swimmer, missing lots of laps with the 935

Collapse
X
  • Time
  • Show
Clear All
new posts

  • Novice swimmer, missing lots of laps with the 935

    I feel like the lap detection heuristics of the Garmin watches are designed with expert swimmers in mind and are failing me.

    I am not an expert swimmer. I swim slow, I have poor form. I don't do flip turns, and my 935 consistently misses laps.

    The thing is, it counts strokes very accurately. I swim a consistently slow 3:00-3:10 minutes per 100 meters, about 14-15 strokes a lap, and the watch gets every stroke. But the watch will just decide periodically that my last 50 meters was actually 25, with twice as many strokes, swum at twice my normal pace.

    If I religiously do a fast tomahawk chop at every turn with my watch arm, I can get it to count almost every lap. But this is not a very natural motion and a frequently forget, ending up with 100 meters counted as 75, or even sometimes 50 (and then it gives me a PR for my amazingly doubled speed). I imagine if I was good at fast flip turns this wouldn't be a problem.

    It's clear that the threshold for turn detection is set far too high, and appears to only trigger very simplistically on the acceleration of your watch arm.

    It's clearly not taking into account swim time, pauses in strokes, or stroke count.

    If you looked at the raw data, there's voluminous information that even a very simplistic algorithm could use to figure out how many laps there were, and when the turn occurred.

    Is there any way to get in touch with the Garmin product managers and get them to take a look at the data from some of us less than perfect swimmers? I don't think it would take a lot of work to dramatically improve lap detection. If you are worried about breaking things for the experts, I imagine you could offer two modes, or a swimming skill level that engages different algorithms,


  • #2
    joshv the algorithm takes into account a number of things to detect a length end and certainly does not rely on tumble turns. I believe that it looks for som break in stroke and a push off of some sort (but doesn't have to be strong push off) it doesn't look at stroke count or swim time AFAIK to help it detect a lap. I occasionally miss laps or have them added maybe 1 in 10 swims at maximum usually where I have taken avoiding action from another swimmer. I swim breast stroke and crawl mainly I turn without tumpling and push off without any violent arm movements. I don't push hard as I am training for open water swimming so I am not interested in my push off contribulting to my times. What stroke are you swimming - get someone to watch you and see what you are doing in the lane or at the turn to see if they can spot any obvious inconsistencies. Whilst the algorithm is not perfect it does work quite well for most garmin users and I don't think the average Garmin swimmer has particularly excellent technique.

    Comment


    • #3
      Have a look here:
      https://support.garmin.com/en-US/?fa...Vb4djrE1lri8i7

      Let me quote a line that might be most important for you:
      • Use a strong push-off from the wall with a long streamlining (glide) phase

      This is what triggers a new lap - gliding for a second without moving your arms. Do it correctly, and you might get 100% accuracy.
      Current: nuvi 255, eTrex 30, Forerunner 310XT, Forerunner 735XT, HRM-Tri, HRM-Swim, SDM4, Virb Elite, tempe
      Retired: eTrex Legend, Swim

      Comment


      • #4
        Originally posted by tmk2 View Post
        Have a look here:
        https://support.garmin.com/en-US/?fa...Vb4djrE1lri8i7

        Let me quote a line that might be most important for you:
        • Use a strong push-off from the wall with a long streamlining (glide) phase

        This is what triggers a new lap - gliding for a second without moving your arms. Do it correctly, and you might get 100% accuracy.
        So yeah, be an expert swimmer, which I am not. I will attempt to emulate. My point is that there's enough data to get this right without me being an expert swimmer. My Fitbit did it nearly perfectly with even worse form. Maybe there's a silly patent involved here.

        Comment


        • #5
          Trust me, you don't need to be an expert swimmer. The glide does not need to be executed perfectly. It is enough if you push off the wall, and keep your arms motionless for a second (literally).
          Last edited by tmk2; 02-11-2019, 08:46 AM. Reason: Switched words.
          Current: nuvi 255, eTrex 30, Forerunner 310XT, Forerunner 735XT, HRM-Tri, HRM-Swim, SDM4, Virb Elite, tempe
          Retired: eTrex Legend, Swim

          Comment


          • #6
            joshv I am far from an expert swimmer and to be honest expert club swimmers are probably not the market that Garmin are aimed at - if you look at "serious" dedicated club swimmers you'll find a very small number with Garmins to track their pool swimming

            Comment

            Working...
            X