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The Tyranny of the Pace Clock

It’s a tool anyone who’s trained in a pool should be familiar with and something coaches and swimming magazines (including H2Open) urge us to pay attention to. The pace clock is that strange looking thing you find at pools that has only a second hand – or more usually two or sometimes four second hands. It’s an essential piece of kit and entire training sessions, if not seasons, are built around its relentless ticking. We use it to set the intensity of our training, to keep track of our progress and ensure swimmers leave sufficient space between each other.
But I wonder, and it’s just an idea with no proof apart from anecdotal observation to back it up, whether it can sometimes hold us back.
The hypothesis goes like this: our subconscious is a cunning thing and essentially lazy. When we put in effort our brain responds to feedback from our bodies and at some point starts sending us messages such as “this hurts” or “if you carry on like that you’re going to blow up”.
But how does your brain “know” if you’re going too fast? It responds to external signals as well as those from the body, such as rate of oxygen consumption or the build up of lactic acid. Have you ever been in a race where you’ve noticed one of your competitors has slowed down and you have suddenly felt a burst of energy that’s allowed you to speed up and overtake? Or conversely, have you been swimming against someone you expect to be slower and felt your energy drain away as they pull ahead? You might rationalise this and say your training has been going really well or that you had a bad day at work or whatever, but is that the real reason or has your brain fooled you?
Similarly with the pace clock. If you use one a lot you become very familiar with where the red hand will end up if you swim a specified distance at a certain effort level. Experienced swimmers will hit their target times to the second, every length. Say you’re doing a swim set such as 16 x 100m and you’re aiming to swim consistently at your 1500m race pace and take 20 seconds rest after each 100m. If you’ve done this a lot you will know exactly how you expect to feel after one, five or 10 repeats.
Now imagine you swim each 100m just one second faster than usual. That doesn’t sound too hard, does it? And you might be all right for five or six but how will you feel after 10? Will you be able to complete the set? It’s only one second, maybe one percent, maybe a little more, but it will hurt. A lot. Your brain will fire off all sorts of pain signals to get you to slow down. But is that partly because your eyes are telling you the pace is too high?
What, instead, if you were swimming your normal times according to the clock but the clock was running a little bit fast? Would your eyes tell you you’re swimming your usual pace so you should feel like normal? Or would you start to think ‘this is hard, I must be having an off day, I’d better slow down’ and you swim slower than usual.
I don’t know the answer but I would be interested to find out.
It would be hard to do this as an experiment. You’d have to design some kind of double blind trial with lots of swimmers randomly assigned to pace clocks some of which kept perfect time and others that ran slightly fast or slow.
But here’s a little test you could try instead. Swim with a watch that can record your lap times but do the runner’s trick of putting black tape over the face so that you can only check how fast you’ve been swimming at the end. Try to swim at your usual pace and intensity levels for the set and see how your times stack up.
If anyone has a chance to do this, let us know how you get on.

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I created Outdoor Swimmer in 2011 (initially as H2Open Magazine) as an outlet for my passion for swimming outdoors. I've been a swimmer and outdoor swimmer for as long as I remember. Swimming has made a huge difference to my life and I want to share its joys and benefits with as many people as possible. I am also the author of Swim Wild & Free: A Practical Guide to Swimming Outdoors 365 a Year and I provide one-to-one support to swimmers through Swim Mentoring.