Back when I started swimming (when dinosaurs ruled the earth), we did not have swim watches; in fact the only time information we had was the race clock and our coaches yelling at us from the pool deck. We could use a Timex watch, but those were frowned upon. No one wanted to be “that guy.”
However, it seems like these days every age group triathlete has a swim watch like a Garmin, Suunto, or Finis. These are nifty devices and while not always accurate, do have several benefits. For one, the swimmer does not have to guess how far they went in a set or workout (note that this is not very accurate when you mix in different strokes, kick sets, or drills, but for 500 repeats are fairly reliable). Moreover, you can easily track your times for each set. The recorded data can also be a valuable tool for coaches and athletes alike after the swim. When people ask me to analyze their data I typically look at several metrics.
Most importantly, I look at splits. The best thing about swim watches is that they record each split when you hit the lap button. I can therefore see if the swimmer slows down from the first rep to the last rep. If the times are consistent, then I know he/she is getting stronger and fitter and therefore should be challenged more with harder splits.
With Garmin files I can also track each length’s time. This is not as accurate as the total time and cannot be used for short distances. However, I can at least get a picture to see if the swimmer slowed down drastically over longer distances (1000m and above).
I also like to look at stroke count to see how many strokes the swimmer is taking per length. Typically I see the cadence slow down as the swimmer fatigues. With the stroke count combined with the time (SWOLF score) I can also see how efficient the swimmer is and track trends with it. A swimmer who has a high stroke count but has very high times needs to work on efficiency while a swimmer who has a low stroke count but still a slow time most likely has a dead zone and is coasting too much.
When I look at open water swim files, I like to see how well the swimmer stayed on course. Slow times can usually be explained by racers, swimming off course.
Swim watch files do have a major flaw though: they do not show the swimmer’s form. I cannot see if you are dropping your elbow; crossing over; or scissor kicking your legs. I need video footage for those.
Overall, data from swim watches have great benefits and can be useful tools but do not rely completely on them for all your swimming needs. A coach is still more reliable.
Coach Chris and Kev