Renowned swim coach Gerry Rodrigues has discussed at length the impact that stroke rate has on open water swimming in many podcasts and presentations, but I like it best when he sums it up like this on one blog: "Don't have a low stroke rate." I love the beauty and simplicity of that statement because it reminds me of what we used to say about safety at a former job I had: "Don't get hurt." Coach Gerry is saying that without attention to stroke rate, we're going to go slow. We need a rate that's not too low and that works for us. So how do we find out what a good stroke rate is?
It is generally accepted that 60 strokes per minute (spm; or 60 arm hits on the water) is considered a "low" stroke rate for triathletes, so we want to be above that for sure. If we have a stroke rate this low, we're probably gliding out too far on each arm and decelerating as we do so. Oh, deceleration, the bane of swimming existence! However, if we ramp your stroke rate up so high that we're spinning our arms and slipping through the water like the roadrunner cartoon (MEEP MEEP), then we're wasting precious energy and we're going to go slow eventually out of exhaustion. Fast doesn't equal fast, as it were.
If you want to dial in your stroke rate, the cool people at SwimSmooth have posted this nifty ramp test that you can use to find out a good stroke rate for you, using a friend and the Tempo Trainer Pro device. If you don't have a Tempo Trainer, or any friends, then first, you will want to go to counseling so that you can get that friend thing sorted out. Next, you can approximate the test somewhat by just swimming a set of timed 8 x 50 (down and back in most pools) after a nice 500 or so warmup. To do the set, start at a super slow stroke rate which feels slower than your normal stroke rate, and slowly increase your stroke rate and record your times. Give yourself adequate rest between each one. If you have a feel for your normal distance swimming stroke rate, you will soon be able to see whether your normal stroke rate ends up giving you a time that's slower or faster than the others. The ideal stroke rate that's most efficient for you for long swims is going to be the one that has the fastest time while still maintaining a comfortable effort. There will be 50s at which you have faster times than this ideal rate, but you didn't feel sustainable or comfortable.
Hint: what you get will be the stroke rate that will help you swim economically at longer distance events without (a) going bananas or (b) gliding too long.