Garmin Swim vs 910xt stroke counts
Today during my warmup I wore both the Garmin Swim and the 910xt on my left wrist. Yes, I looked like a freak/geek, whatever. But I wanted to compare the output because after my first workout with the Garmin Swim I had a feeling it counted the strokes differently.
And it does. The warmup was 400 yards and here's the comparison:
| GARMIN 910xt |
GARMIN SWIM |
|
| Interval | 1 | 1 |
| Swim Stroke | Freestyle | Freestyle |
| Lengths | 16 | 16 |
| Distance | 400 | 400 |
| Time | 06:30 | 06:32 |
| Avg Pace | 1:37 | 1:38 |
| Best Pace | 1:27 | 1:31 |
| Avg SWOLF | 34 | 36 |
| Best SWOLF | 31 | 33 |
| Avg Efficiency | 37 | 39 |
| Best Efficiency | 34 | 36 |
| Total Strokes | 150 | 175 |
| Avg Strokes | 9 | 11 |
| Min Strokes | -- | -- |
| Calories | 69 | 64 |
Inability to press the lap buttons simultaneously is why the times are different (I started the 910xt second and stopped it first). The point here is the stroke count. The 910xt counted 150 strokes. The Garmin Swim counted 175. That's a huge difference. I know in the DC Rainmaker review of the Garmin Swim he mentioned that a lap is triggered more quickly on a wall push-off with the Garmin Swim, so I assume the accelerometers and/or software are different. But really, how do you count 25 strokes differently in 16 lengths??????
Comments
one thing is that usually the first stroke counted is the first arm that moves, so if after pushoff, you typically take the first stroke with your right arm, then I think the watch on your right wrist will be more accurate. Having said that, I have a garmin swim and before that a finis swimsense. I also mentally count my strokes a lot. I take the numbers on the watch with a grain of salt, but have found the swim to be generally more accurate in the pool. I have only worn the 910xt in the pool a couple of times so can't comment there.
I push off and then take my first stroke with my right arm (garmin on left) so I guess I need to add 1-2 strokes to the 9-11 the garmin is reporting per 25yd length.
Not sure I buy into the whole less strokes per length is better anyway , the avg SWOLF makes some sense since its time per length + strokes per length.
In the end I really dont care about anything other than time anyway.
During my cool downs I usually do back/breast strokes and twice the Garmin has counted an extra length when doing back stoke. Must be how I turn around it counts it twice.
Thanks for posting this. I put a rhythm counter in my hat while swimming and try to stroke every time it beeps but my 910 is always 10-15 beats more. I've tried only flip turning or just pushing off the wall minus the flip and they are about the same.
Curious of your opinion on Garmin swim watch vs the Swimsense. My Swimsense is dying a slow death (won't upload workouts anymore, band is deteriorating). I have a 310xt that is still kicking, but I've been floating the idea of just getting a 910xt to replace both the aging 310 and the Swimsense, or just getting a Garmin swim watch and keep rocking the 310.
Trevor: My swimsense died the way you are describing. It was only a couple of weeks past its 12 month warranty and Finis wanted 75$+shipping (USD) to send me a new one, so out of spite I bought the swim for 150 CAD$.
I liked the swimsense to a point. It had better customizability than the swim, but I have now gotten used to the Swim screens (it allows you to have only 1 customizable screen vs every screen on the swimsense). The Finis online dashboard is also better for deconstructing your data than garmin connect. The Swim is better for readability of the screen, use as a watch, and also ease of downloading data to your computer over ant+. It has also been very durable and doesn't look or act any different than when I got it over a year ago. There have been at least 2 firmware upgrades in that time which have fixed the odd bug and added functionality as well. I also think the swim is better than the swimsense in counting laps, but this may be peculiar to me as opinions seem to vary on the internet in this regard.
I have been using the swim for a year and really like it. I like that it can be worn as a regular watch. I did use my 910xt a few times in the pool when I was in between watches but I got nervous about exposing my 450$ watch to chlorine on a regular basis, as well as leaving it to freeze in the trunk of the car all day while I was at work (at that time pre-EN I was swimming a lot). I also found the face of the 910xt started to fog a bit when running outside so that scared me too (was water leaking in?). Apparently this is a known issue with the 910xt. The Swim also has more swim specific features (like 'drill mode' for instance). The swim can only be used in a pool as it has no GPS ( same for the swimsense).
However the 910xt imo is far better than the 310xt (which I also had until I lost it). The open water swim capability is pretty cool and I find it does better with satellites and downloading data than the 310xt did.
910xt would be fine as a one use fits all watch and for races if you really need to replace the 310xt, however I think the Swim is better than the swimsense, and better as a standalone pool swimming watch than the 910xt.
When I am mentally counting strokes, I count when my hand goes in (generally my right hand). The 910 (worn on my left) reliably gives me the exact same number, because 99% of the time, there is a left pull accompanying the right entry. I can't flip turn to save my life any more. Unlike riding a bicycle, I somehow forgot this skill I was never very good at at anyway. I can believe there MIGHT be a difference if you flip turn because of all that extra motion of a poorly done one...but a good flip-turn will still have a systematic relationship. You are supposed to put both arms back and not use them during your flip... but if they waggle around a lot, who knows what is going on there.
I touch turn with my right hand almost 100% of the time, and that same almost 100% of the time, my left arm is down at my side, having pulled.
I don't know exactly what triggers the count, but you MIGHT get one count different per lap systematically if you wear it on the other hand and turn cleanly. Otherwise, it should make no difference. And remember, "real swimmers" count both hands, so that "10" is really either 19, 20, or 21 to begin with. :-)
Of course, I have no idea how to answer the original question except to suggest that Matt re-do the experiment and actually count in his head what he thinks the number should be.
Which watch the arm is on might make a difference if you are wearing a watch on each arm and comparing. I agree that the watch will agree with my mental count most of the time, but I'm not sure if this will hold up if you are comparing watches on each arm.
I almost always take my first stroke (pull) with my right arm. Therefore if the watch is on my left arm it will always be half a stroke cycle behind. So the right side watch might count 10 right arm strokes (20 in total) but the watch on the left hand may count 9 left arm strokes and give you a count of 18. If you do 50 lengths, one watch might be 100 strokes behind the other give or take.
My garmin swim doesn't seem to care which arm it is on. Interestingly, it sometimes also gives me odd number counts, ie 17 or 19 or 21. Not sure how it deduces this. The swimsense watch instructions ask you to input which arm you are wearing it on, however, and always gives an even number i.e. for me 18 or 20 spl.
Repeating the experiment but switching the watches to the opposite arms should give a result skewed the opposite way.
Just an FYI....no answers here...I have the Garmin Swim for my pool work and absolutely love it....HOWEVER...it does occassionally miscount....and if you think something is amiss with the total/time ...just look back throught the intervals...and you will typically find that it missed a turn/lap...don't see it much in short stuff 100/200/400 but in longer sets...maybe do to the lazy turns...it misses...today in a 1hour swimset...when I stopped it said 58:00 2900yds 2:03/100....(and I new I was swimming faster)...so when I reviewed the data..it missed 10 laps (ie. I swam 3150 in 58:00 or 1:53/100)...its easy to see where it misses...so not a big deal....
FWIW- I think the stroke count is more accurate than the 910....does the 910 have an accelerometer? How does it calc. Strokes?...
My question is always trying to figure out what "event" triggers the length at a turn and at a touch. If you actually add up the length times for a "lap", they are usually a little less than the lap time, meaning the time where you push the button. Not that it matters much. :-)