This is a simple math equation we use in swim training to measure performance (in terms of time) in a test or race:

Pace = Strokes Per Length x Tempo

By counting strokes (SPL) over a certain distance and multiplying that by the Tempo, we can calculate Pace. Or we can take Time (seconds it took to complete a distance) and divide that by SPL, we can calculate Tempo. Or we take Time and divide that by Tempo to calculate SPL. When training for Pace control we need to track two of the three variables (Time, SPL, or Tempo).

In the pool, we need to factor in the time and distance of the push-off from the wall (or the flip-turn) into this equation. But I’ve discussed that already  in another post.

Speed, technically speaking, is not exactly the same thing as Pace.

For the math geeks the units go like this:

  • Speed = Distance/Time
  • Pace = Time/Distance

Speed and Pace are the inverse of each other.

Speed is rather hard for us to grasp in our heads – do you know, without doing a little number crunching in your head, if swimming 1 meter per second is ‘fast’ or not? Most people don’t.

Yet Pace is a rather familiar measurement for us to use and compare – we might quickly understand that swimming 1:30 for 100 meters in decent, and swimming under 60 seconds for 100 meters is impressive. So we like to use Pace most often.


Pace, in terms of physics, means the amount of time it takes to cover a certain distance. We might say that a swimmer has a pace of 1:30 (90 seconds) for 100 meters, or he swam 25 meters in 22.5 seconds, or she finished the 1500m swim portion in 27 minutes. These are all referring to pace.

Pace, in terms of physiology, means the manner in which the swimmer has used his limited energy over that certain distance. If a swimmer is able to hold a steady Pace we may infer that he has distributed his energy evenly over the swim. A steady Pace is a desirable accomplishment.

To see if someone won the race or not we may look at the overall finish time. But if we want to examine how well a swimmer has used his energy across that race, to see if he might be able to use it better,  we often want to look at the Splits (split = the amount of time on a single length, or on an evenly divided section of the race) to get an idea of how much control he had over energy expense. We use Splits to determine Pace, and then we want to look deeper into how that swimmer constructed that Pace: what SPL and Tempo did he use? How did it change? Why? Could it be made better?

We could divide a 100 meter swim into 4x 25 meter Splits (in a 25 meter pool). We could divide a 400 meter swim into 4x 100 meter Splits. We could divide a 1500 meter swim into 3x 500 meters Splits, (or 15x 100 meters splits).

For an example of how Pacing may play out in a race, let’s look at 3 swimmers (assuming all of similar fitness and effort level) and compare their splits for 400 meters:

Pace comparison

You can see that Swimmer A started out the fastest on the first length (72 seconds for the first 100 meters), but was going the slowest on the last length (84 seconds for the last 100 meters). He achieved the slowest time overall, and that is reflected in his average pace of 78 seconds per 100 meters. He represents the typical results of a swimmer with insufficient pace training (both in body and mind).

Swimmer B started out a little slower than Swimmer A but held that pace fairly consistent during the entire race and achieved a faster time. He represents the results of a swimmer who has learned the fundamentals of Pace control.

Swimmer C started out slower than both A and B, yet he gradually increased his Speed from Split to Split, and achieved the fastest time of all. He represents the results of a swimmer who has mastered Pace control and now plans how to distribute energy for the best race results.


The Speed Challenge is to reach a certain velocity.

The Pace Challenge is to sustain that velocity over a certain distance.

The Efficiency Challenge is to use the least energy-expensive way to sustain that Pace. The skill of Pacing is essentially the skill for managing energy.

Two swimmers moving along at the same Speed are not necessarily equal in skill in how they manage energy. Finish times do not determine efficiency – a Fast Stroke Technique is not necessarily an Efficient Stroke Technique. There is an energy-expensive way to produce speed and an energy-conservative way to produce speed. Both swimmers may achieve the same Speed, and then sustain the same Pace – but the swimmer who is producing Speed at less energy expense can choose to either increase Pace over his opponent or sustain Pace longer than his opponent, or save that energy for use somewhere else (as in a triathlon).

A pure swimmer will aim to produce as much Speed for the amount of energy they have to spend, and finish the race completely depleted. His efficiency (using as little energy as possible to produce as much Speed as possible) allows him to sustain a higher average Pace than his opponent.

A triathlete, on the other hand, will aim to produce just enough Speed, using up only a certain amount of his available energy to hold that Pace, so that he can get out of the water in a relatively good position while preserving a sufficient amount of energy to accomplish the more win-critical sections of the race.

Both kinds of swimmers need to find ways to reach then sustain higher Speeds, using less energy than their opponents.

Lesson: If you truly care about efficiency it is not enough to just crank up your Tempo to increase Speed – you must consider how you produce Speed and construct Pace, at what energy expense. If there is a less-expensive way to produce that Speed, it behooves you to find it.

This is what Pace training is about.

First, learn fundamental Pace control, like Swimmer B. Then, with that skill in place, you can master Pace control and manipulate it for even better results, like Swimmer C.


View the whole Metrics Series:

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