Vasa Swim Erg – ‘Properly’ Record the ANT+ Power Data as you swim

Vasa ErgVasa Swim Erg – Record the ANT+ data properly on your Garmin

Unsurprisingly, this year VASA sold out of their indoor swim ergs as we were all locked out of our favourite pools.

Pools are now opening in some parts of the UK though I’m not sure about elsewhere, so if you are currently unable to swim, you might be delighted to learn that Vasa has just taken delivery of a recent production run. Is now the time to future-proof your swimming against further lockdowns? I thought so.

What is the Vasa Swim Erg?

It’s essentially a modified Concept II rowing machine but for simulating swimming with two paddles.

It displays all the stroke, distance and time metrics you’d expect plus dual-sided power and a metronome. Even more excitingly, it broadcasts some of that data over ANT+ so you can record it as proof that you suffered in your pain cave on yet another torture machine.

On the downside, it’s a bit uncomfortable; you can’t replicate proper rotation; it’s a fairly old design that needs updating and improving; and it comes in at an eye-watering $2299 for the ANT+ version. So…I bought one.

My data-related goal is to build a swimming power critical power curve. Sad. But true 😉

More: Vasa Trainer

Vasa’s Data solution

Problem: There is no swimming profile that is power-enabled by default.

The official data solution from Vasa goes back to the early days of power when STRYD and every other non-cycling power meter initially said ‘Just record your workout in cycling mode and change the sport later‘. Vasa’s solution kinda works but I’m currently planning on swimming 6 times a week now that I only have to walk to the shed and so I don’t want to waste too much time faffing around with FIT files and the intricacies of workout editing on TP/Golden Cheetah.

Plus, whilst that ‘kinda works’, it doesn’t capture the stroke dynamics that a swim profile would, nor does it leverage some of the fancier Garmin swim features like automatic rest interval detection. If you have inadvertently linked your Garmin Connect account to multiple other platforms then you may well soon find yourself with having to edit the recorded sport on several platforms (Strava, TP, GC).

A Better Solution

Well, the Vasa CIQ Data Field would be the best solution…but there isn’t one. So we are left with ingenious workarounds.

To cut a long story short, here is the workaround…and it’s a good one.

  1. Copy the open water swim profile and rename it to ‘Vasa’
  2. Download a CIQ data field that is designed for cycling such as Bike Power (@NikeOW) or ANT+ Power Meter (@Takura87)
  3. Insert the data field into the Vasa profile and off you go (PM power and PM cadence will be recorded, plus whatever else the sport profile records on the device you use)
  4. Of course, you won’t be able to see anything on the watch as it will be on your wrist. The Vasa display is also pretty hard to read so you might hopefully also have an ANT+ bike computer to replicate that setup and display the information directly below your face.
  5. Perhaps an even better solution would involve an iPad, a decent box set and an ANT+ Dongle to convert the power data to BLE and display it on the Wahoo Fitness app on the iPad? These clever pieces of tech will probably convert ANT+ to BLE too
    1. 4iiii Viiiiva. I have one but it seems to have broke.
    2. NPE Cable (Pod)

As an aside, I’ve also cranked out my Humon Hex muscle oxygen sensor (now only sold in Spain) which handily straps around my chest and holds the sensor onto a lat muscle. Cool! The SmO2 data fields still work so I’ve added those to my Garmin Vasa profile too. I had problems using my HRM-PRO which was EXTREMELY uncomfortable when pressed against a bench and as a result, the HR signal couldn’t be picked up by the FR945, this gave the perfect opportunity to use my Polar OH1+ HRM on my arm to see instantaneous and accurate HR on all the active devices over ANT+/BLE. Finally, I could perhaps wear my FORM Swim goggles with their Heads-Up Display but that is DEFINITELY a gadget too far when it comes to shed-based usage! So I won’t do that.

After the workout is completed, Golden Cheetah and Garmin Connect both seem to automatically recognise the power data and, in the case of Golden Cheetah, I now have a swim-specific critical power curve. The power numbers are a fraction of what they will be for bike or run and so I’m too embarrassed to show my curve right now 😉 (FTP less than 100 !)


Please treat these suggestions as an unfinished solution. There may well be ways to improve my solution. If so, please add comments below.

The issues that remain for me are that

  • I can’t seem to get a data field to record any power when using a Pool Swim profile. Hence why I copied and used the OWS profile. Pool swim would be a nice profile to use because of the extra metrics it has and because of features like drill mode and auto rest interval detection. Workouts recorded as ‘Pool’ sometimes also trigger advanced features in other pieces of software like SportsTracks.
  • @Takura’s data field seems to only record total power and not LR power.
  • @NikeOW’s data field is able to record cadence, power, power balance from the PM. The free data field displays 7 metrics (and only 7) so your desired power number might appear too small.
  • The activity is recorded in Garmin Connect as an ‘Open Water Swim’ sport. (I’m OK with that)
  • The recorded pace is probably based on wrist movement of my FR945. The numbers seem vaguely plausible but probably come out on the ‘too fast’ side. Whereas the pace/100m on the Vasa seems good.
  • Consequently recorded distance probably reflects the inaccuracies inherent in the PACE calculation.
  • Vasa confirm that they broadcast all the following and so all these could be recorded by an appropriate CIQ field: time, speed, distance (needs bike wheel circumference set to 100mm if that option is available), power (L and R) and cadence.



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4 thoughts on “Vasa Swim Erg – ‘Properly’ Record the ANT+ Power Data as you swim

  1. did you ever manage to improve on the method of recording data from vasa to garmin by chance?

    1. other than those methods above, no.
      it depends on exactly what you want to achieve as to what is the best solution for you
      i wanted power in swim mode so @Takura’s CIQ field in a copy of the OWS profile works well for me. you cant use a chest strap without pain so i use Polar Verity Sensose/OH1. this method also puts the power in golden cheetah to create a power duration curve and that was all i wanted. I’ve not looked at all at following a swim power plan or power structured workouts and don’t even know if it’s possible to create one that can be executed in swim mode (might be possible )
      FYI: The swim metrics likely wont work as the vasa stroke is not the same as the real stroke as you know.

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