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by Stuart McDougal

June 19, 2015

Using a little math to find the right tempo, stroke length, and pace

Conventional wisdom tells us that faster freestyle turnover equals faster speed. If only it were that easy! This might be true for our terrestrial counterparts, runners, but water is about 800 times denser than air. That added resistance means the rules don’t apply in the same way for both runners and swimmers. Additionally, turnover rate and speed don’t share a linear correlation; errors in stroke mechanics introduce drag, and as speed increases, this drag coefficient increases exponentially.

Finding the right turnover is personal and based on a swimmer’s height (or wingspan), skill level, tempo (rate of turnover), and stroke length. Tempo is measured in strokes per minute or seconds per stroke. For example, 60 SPM is equivalent to one second for each arm stroke. Stroke length is the distance the body moves forward on every stroke.

As many short swimmers already know, height is an advantage in swimming. Taller swimmers naturally have a longer stroke length. But shorter swimmers might be able to overcome some disparity if they access the legs effectively. This is why counting kicks per length is important to finding whether more (or fewer) kicks increase stroke length and speed or just burn up more energy than necessary.

More often than not, swimmers stroke at tempos that are too fast—beyond their current skill levels—and are forced to kick too much so they can remain stable. These swimmers might be physically able to spin their arms at 70 or 80 SPM, but they don’t get the return in speed they should given their stroke rate and added kicks. In addition, that higher stroke rate typically deteriorates in mid- to long-distance swims or toward the end of a main set at practice. The swimmer attempts to swim more yards to build endurance and manage fatigue rather than improving technique and skill to get the most out of each stroke and avoid fatigue.

Basically, they’re swimming harder instead of swimming smarter.

Getting accurate measurements for tempo, stroke length, and pace can be a challenge, especially in 25-yard pools, but you can help your swimmers accomplish this with some planning and a little math. Let’s start with measuring tempo.

Measure Tempo

Although some swim watches count strokes and estimate tempo, these devices sometimes offer inaccurate data because they monitor only one arm. A more accurate way to measure your swimmers’ freestyle tempo is a good old-fashioned stopwatch.

To measure a swimmer’s tempo, start the watch on the first hand entry and stop the watch on the last hand entry while counting each stroke (or hand entry). Measuring a swimmer’s tempo for 8 to 10 strokes will provide an accurate stroke rate.

  • Tempo = time per stroke. Example: 7.0 seconds / 8 strokes = .875 seconds per stroke, or ~70 SPM (8 strokes x .875 seconds = 70)

Measure Stroke Length

This requires stroking a true swim distance and excluding the glide off the wall. In a 25-yard pool, I have swimmers start their strokes at the flags (5 yards from the wall) and then count their hand entries for the rest of the length. In this case the true swim distance is 20 yards, which makes calculating stroke length simple:

  • SL = yards/SPL, e.g. 20 yards / 15 SPL = 1.33 SL (1.33 yards or 4 feet)

Calculate Pace

Normally, the pace clock is used to determine, as the name implies, a swimmer’s pace. Unfortunately the pace clock can’t distinguish starts, turns, and glides off the wall from the actual swim distance, but it’s important to separate swim distance from those other elements. Separating it gives you actionable information about where to improve the swimmer’s times, whether to use longer or shorter glide distances, how to improve stroke and/or turn efficiency, or some combination of these items.

In addition, there are no walls in open water racing or triathlon, so if you’re working with a triathlete or open water swimmer, it’s only necessary to measure swim distance. This eliminates the problem of accounting for an athlete who has a poor or inconsistent turn.

Calculating pace is simple and based on a familiar formula:

  • Rate = distance/time (r=d/t), or in a swimming context, Pace = SL/Tempo

For example, let’s say your swimmer has a: SL = .83yds (24 SPL), Tempo = .85 seconds (72 SPM): 

»      Pace = .83y/.0.85s = 0.98 yards per second

»      100-yard pace = 100y/0.98 = 102 seconds or 1:42.00

»      1-mile pace = 1760y/0.98 = 1795.9 seconds or 29:55.90

»      2.4-mile pace = 4224y/0.98 = 4310.2 seconds or 1:11:50.40

Here’s an example of a 5-foot, 10-inch-tall IRONMAN triathlete who recently joined my squad. He came with a high turnover rate and a 6-beat kick. His high stroke rate and kick tempo lead to significant drag production, which was inefficient and exhausting.



.86 seconds per stroke, or 70 strokes per minute (SPM)

Stroke length (SL)

.77y or 26 strokes per length (SPL)


.77y / 86 = .90 yards per second

100-yard swim

100y / .90 = 111.1 seconds or 1:51.10

2.4-mile swim

4224y / .90 = 4693.3 seconds or 1:18:13.20


Approximately 5,500 strokes in 2.4 miles


Approximately 16,500 kicks in 2.4 miles (using 6-beat kick)


To decrease the amount of drag production and increase his efficiency, we reduced his turnover, improved his stroke length, and switched him to a 2-beat kick.



1.05 seconds per stroke or 57 SPM

Stroke length (SL)

1.18y or 17 strokes per length (SPL)


1.18y / 1.05 = 1.12 yards per second

100-yard swim

100y / 1.12 = 89.3 seconds or 1:29.30

2.4-mile swim

4224y / 1.12 = 3771.4 seconds or 1:02:51.40


Approximately 3,600 strokes in 2.4 miles


Approximately 3,600 kicks in 2.4 miles (using 2-beat kick)


These changes shaved 22 seconds off his 100-yard pace and 16 minutes off his 2.4-mile IRONMAN swim. But, perhaps most important, is the energy savings he experienced—he dropped approximately 2,000 strokes and 12,900 kicks in the 2.4-mile Iron-distance swim. That’s a lot of saved energy, which can be used for faster bike and run times.

There isn’t one best turnover rate—it’s about finding the right tempo for each individual swimmer given height and skill level. Swimmers need to find rates that are sustainable for their swim distances or events.

Knowing how to calculate your swimmers’ tempo, stroke length, and pace will provide important information that will enable you to help them find better efficiency and energy savings in the water.


  • Technique and Training


  • Freestyle
  • Stroke Technique
  • Pacing