Over counting Swim laps

DanCarrot Registered Users Posts: 2
New Traveler
edited January 24 in TomTom Sports
Hi everyone, my multisport cardio seems to count around 50% more lengths in the pool than I actually do. I have no idea why, it lays about 4/5 lengths before it starts going a bit crazy. I just don't understand why. It's weird because my wife has the same watch and at worse hers is only ever 1 or 2 lengths out. It makes switching off impossible as I constantly have to count myself and totally mucks up my records on the app, can't see if I'm getting faster or anything.

Any thoughts welcome. I have checked and it's set to metres and all that jazz.



  • lampard
    lampard Administrators Posts: 5,952
    Hi DanCarrot,

    Welcome to the Community & sorry about the delay in response!

    The watch counts laps in the same way it counts strokes, by the accelerometer. There are some situations that affect the measurement of swimming statistics, you can find them here: My GPS Watch reports the wrong swimming statistics. What can I do?

    You can also set an auto lap for the distance of the pool which should alert and record a lap for each length. Perhaps some other users here can help you find suitable styles to get the results.

  • tfarabaugh
    tfarabaugh Posts: 16,936
    Miscounting laps is common with most swim watches to some extent. It is using an accelerometer to try and figure out when you are reaching for the wall to turn, but you need a very strong turn to trigger it. It also counts after the first turn, so the total is the laps completed so it will always be one short until the end. It is likely you did not register the final lap as you probably coasted to the wall. Make sure on the final lap that you have a strong finishing motion so it registers the movement. It may be worthwhile to simply turn on the final lap and then stop so it registers the turn and hence the lap. You also need to be consistent in your stroke (freestyle works best), do not pause or slow at all mid-lap, among other things. It counts strokes in the same way it counts laps, by the accelerometer, so any variation in stroke may cause it to miss a stroke. Just like with lap counting, it is meant to give a rough estimate, it will never give you a perfect count, the technology just isn't there yet. If you search for swim accuracy or swimming laps and similar phrases on the forums you will see plenty of posts on it with a lot of suggestions to improve it (more than I can repeat here) including:

    - Consistent style and pace per length gives the best measurement results:
    - Stick to the same stroke type per length.
    - A dramatic change in pace part way through a length may cause errors.
    - A strong push off the wall helps.
    - Please make sure your height, weight and gender is also correct.

    You can search the forums for swimming accuracy related posts (try a variety of search strings) and will find a lot of posts on it. In a nutshell, it is only an estimate and is highly variable based on the user. You need to be using a consistent stroke (freestyle is best), push very hard into the turns (it recognizes a turn by the accelerometer using a force thrust), do not pause mid lap, among other things. You will never get laps using a kickboard as it is using the accelerometer built into the watch to sense strokes by your arm movement. There would be no way for it to measure strokes and laps if your arms are not moving.

    I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.
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