Watch the Clock


Most seasoned swimmers understand the value and importance of watching the pace clock while swimming.  Whether doing an easy warm-up or an intense set, keeping an eye on the clock at all times is important.  This article is primarily targeted at people new to the sport of swimming but hopefully will also provide some good information for long-time swimmers.

Reading a Pace Clock

Analog pace clock

Analog pace clock

Let’s get everyone comfortable with some terminology first.  Traditional pace clocks are analog clocks with two hands: one for seconds and one for minutes.  They lack an hour hand and the clock itself has seconds written on it instead of hours.  So the “top” of the clock reads “60” (instead of “12”) and the “bottom” of the clock reads “30” (instead of “6”).

Swimmers often refer to “60” or “0” as “the top.”  So when someone says “OK, let’s start the set on the top,” that means they intend to push off the wall when the second-hand gets to the 60 (the physical top of the clock).  Similarly, swimmers often refer to “leaving on the bottom”, as pushing off the wall when the second-hand reaches 30.

Other common yet confusing term, at least for people new to the sport, is “leaving on the side.”  This refers to pushing off the wall when the second hand of the clock reads either “15” or “45.”  Typically it’s whichever is nearest to where the second hand is at the time the statement is made.  People sometimes also say “let’s leave on the east side” or “leave on the west side,” which would be pushing off the wall on the 15 or the 45 respectively.

When using a digital pace clock, the terminology is the same (0/60 is top, 30 is bottom, 15 and 45 are the sides) despite the fact that there is no second hand to give it the same meaning as in the case of an analog clock.

Using a Pace Clock to Time Yourself

Using a pace clock to figure out how fast you’re swimming is quite easy with some simple math.  For example, suppose you push off to swim a 50 freestyle on “the top” and when you get to the wall after finishing, you look at the clock and see the second hand is pointing at the 40.  That means you swam the 50 free in 40 seconds.

Suppose you want to do a set of five repetitions of 50 freestyle leaving on a 50-second “sendoff,” meaning that every 50 seconds, you start another repetition of 50 free.  This could be done by starting the first repetition on “the top” and then doing each repetition 50 seconds after that.  So the second one you would be pushing off as the clock reads 50; the 3rd repetition you’d leave on the 40; 4th on the 30; and the 5th on the 20.

During this set, you should also be making note of what the clock reads when you touch the wall.  That way you can do some simple math to figure out how long each repetition is taking you to swim.  Taking the above example, suppose on the 3rd repetition you finished, you touched the wall when the clock read “21.”  To figure out how long that 50 free took you to swim, you can figure that the time elapsed from when you left on the 40 until you touched on the 21 is 41 seconds.

Why use a pace clock?

There are many good reasons to use a pace clock.  The primary reasons for using a pace clock are to:

  • Know how fast you are swimming,
  • Understand and practice pacing, and
  • Get a better and more consistent workout.

It is very important to know how fast you are swimming because practice times are an exact measurement of our performance.  By watching the clock we can measure our performance every day, which gives us instant feedback about how we’re progressing (or regressing).  I find watching the clock and measuring performance to be a great way to self-motivate during a hard set, especially when swimming alone.

Even when warming up and cooling down, it’s good to keep an eye on the pace clock so you can develop a feel for swimming at different speeds.  This is especially valuable for distance swimmers who might want to maintain a slow pace for a long time, for example during an 11-mile down-river swim in the Willamette River in July!

Doing sets on a sendoff that allows for some fixed amount of rest, which can be varied depending on the goal of the set, allows for keeping one’s heart rate in a target zone for an entire set.  In this way, choosing a proper sendoff and watching the clock can help to dramatically improve the quality of your workouts when working toward a goal time for a particular event.  And choosing an interval wisely can also help keep track of the number of repetitions completed.

Watching the clock and doing the same or similar sets from time to time can easily tell us if we’re improving day-to-day.  It can also let us know if we might be getting sick or if we might have a potential health issue.  I’ve heard stories of swimmers who figured out they have a heart condition based on the fact that they were significantly slower one day than they were the day before.  If you’re watching the clock every day and notice a serious and significant slowdown in your pace, that could be a signal that you’re getting ill or have some health condition that may need to be addressed.  Who knows, watching the clock could very well save your life!

For those new to the sport of swimming, I hope this brief article provides a clear overview of how and why we use a pace clock.  Outside of goggles, I think a pace clock is the most important piece of equipment for swimming.  Learn to use the pace clock well and you’ll appreciate the key role it plays in training to swim well!

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