By Steve Brodsky and Joe Petrush
In part one of this article, we introduced you to three technical elements you can use in your swim. Now, we’re going to introduce you to two metrics you may be able to use in the pool: stroke rate and stroke length. Terry Laughlin, founder of Total Immersion Swimming, was one of the first coaches to work with these these metrics and show how they can provide an indication of our swimming in a similar way that measuring power can yield valuable data for cyclists. We now know that learning to calculate, manipulate and personalize stroke rate and stroke length yields tremendous gains for swimmers.
Stroke rate (SR) is a measurement of how many strokes you take in a minute. In other words, it is a measure of how quickly or slowly your stroke is turning over. To manipulate stroke rate, swimmers can utilize a tempo trainer (TT), a small swimming metronome. The TT, when placed in the swim cap, beeps at a fixed interval. The swimmer adjusts her stroke so that her lead hand is reaches maximum extension with the beep.
Stroke length (SL) is a measure of the length a swimmer travels with each stroke. We typically calculate stroke length by counting the number of strokes a swimmer takes per fixed distance, usually a length in a pool. Since most of us swim at the same pool with regularity, focusing on strokes per length (SPL) is the easiest way to quantify stroke length.
Stroke length is influenced, primarily, by three factors: your body length, your technique (as discussed in part 1 of this article) and your swim fitness. We’ve learned that the best swimmers in the world cover more distance per stroke (they take fewer strokes per length) and they maintain that number of strokes per length across their swim.
A great example of this is Sun Yang’s world record-breaking 1,500-meter swim at the London 2012 Olympic Games. As analyzed byCamelback Coaching, Yang holds the same SPL across the entire 1500 meter swim (a mere 13 strokes per 25 meters). He also maintains a fixed stroke rate of about .96 for the majority of the swim. And, when he does increase his rate at the end of the swim, his SPL does not change.
From these ideas, we focus here on two goals using stroke rate (SR) and strokes per length (SPL):
1. Find the lowest number of strokes per length that you can maintain with consistency at a fixed rate and then work to lower those numbers. For example, if you determine that you can hold 16 strokes per length at a rate of 1.8 with consistency, work to lower the SPL to 15 at 1.8. And, also, work to lower the SR to 1.7, then 1.6 while consistently holding that 16 SPL.
2. Using the SR and SPL you established, work to elongate the distance at which you fall off the mark. In other words, if you are able to maintain 16 strokes per length at 1.8 consistently for a 200-yard swim, try to elongate that swim to 250 before you start adding strokes or miss the beep.
Why do we focus on these goals? Numerous studies (Costill et al. 1985, Craig and Pendergast 1979, Maw and Volkers 1996) and swim experts have established that speed = SR x SPL. In other words, going faster comes out of controlling the metrics, like with bike and run.
Here’s a simple example: If you swim 25 yards in 10 strokes and at a rate of 1.5 (1 stroke per 1.5 seconds), you’ve just swum 25 yards in 15 seconds (1.5 x 10 =15). By decreasing strokes per strength or by increasing the stroke rate (faster rate), we change the equation and create a faster swim:
- 9 x 1.5 = 13 seconds (faster by decreasing SPL)
- 10 x 1.4 = 14 seconds (faster by increasing stroke rate)
In both examples, a faster swim comes through manipulation of SR or SPL, from smarter swimming not simply going harder. Moreover, in addition to easy swim power gains, we have two true measures (SR and SPL) to help you quantify your gains.
As you begin to train with SR and SPL, start by becoming comfortable counting your strokes for each length of the pool. Each time your hand enters and reaches maximum extension, that is one stroke. Once you are comfortable with counting strokes, get comfortable with the tempo trainer. Find a comfortable rate — experiment with rates between 1.1 and 1.8. Now swim at that rate, “matching the beep,” each hand reaching maximum extension with each beep.
After you are comfortable counting strokes and swimming with your TT on a fixed interval, you can begin to combine the two and work on the goals we mentioned. Here is one example of how to mix this sort of training into your current swim routines:
4×50 with decreasing SPL
With your TT at 1.5, swim one 50 at a comfortable rate of perceived exertion (RPE). Count your strokes and try to take one fewer stroke per 25 for each of the next three 50s. So if you swam each length of your first 50 in 18 strokes per 25, try to swim your second 50 in 17 strokes per length, your third 50 at 16, and your final 50 at 15.
Variation: Try substituting manipulation of SR instead of SPL. For the second, third, and fourth 50 of the set, maintain your SPL while increasing your SR (faster TT setting) by .05 for each of these 50s. (Your first 50 is done at 1.5, #2 should be at 1.45, #3 at 1.40, and #4 at 1.35.)
Ultimately, you should work to elongate the distance you need most work. If you can hold a combination of SR and SPL for 100 yards before adding strokes or slipping off the beep, try stretching that to 125 and 150. You’ll find that mental focus and technique are key elements in holding the strokes per length and stroke rate. Note your gains and enjoy the process.
Steve Brodsky is a professional writer, English professor, and avid triathlete. Along with his writing partner, Coach Joe Petrush, he has written articles, newsletters, coaching manuals for USAT, and two chapters in a forthcoming triathlon book for over 50 iron-distance triathletes.
Joe Petrush is a certified USAT Level II coach and race director. Additionally, he is a Total Immersion swim instructor. Joe has participated in USAT’s elite mentorship program at the Olympic Training Center in Colorado and frequently shares his knowledge at USAT coaching certification clinics. Joe is the founder and head coach of both Bayshore Swim and Premiere Coaching.