I do get a lot of questions from triathletes that are suffering with their swim training.

The Right Pace

I can run a 10K run without a problem and go out for a bike ride of 80km without a problem.....
but why am I exhausted after a 400m swim?

Of course, a big part of this question can be answered by a poor swim technique and this remains top priority to improve both your swim pace and swim efficiency. But still, I do see a lot of swimmers with a relative good technique, swimming with the same pace all the time. They jump into the pool and do a long continuous swim at the same pace (and very often to fast). Why are they doing this? Why don't they train with different paces as they are doing on the running track....? And how to determine the right pace to swim ?

Just as for cycling and running, there are also various methods to determine the different pace zone's in swimming. These methods include, but are not limited to, lactate testing, 30min tests, 1000m test, Critical Swim Speed test (CSS).....
For the last couple of seasons I have been using the 30min test as described by Jan Olbrecht (The Science of Winning: Planning, Periodizing and Optimizing Swim Training). I found that this test was providing a good enough estimate of the training paces for the level of triathlete's I was working with. It's not as accurate as the lactate testing but you only need a stopwatch to perform the test. Based on the test result, a matrix was compiled that contained training times for various distances, various intensities and various rest intervals as shown below :

This test however does not provide you any information on the anaerobic capacity of the swimmers. The big disadvantage of this test was that going all out for 30 minutes is very demanding and needed to be scheduled very carefully and not to often.
This disadvantage was the trigger for me to search for an alternate method that is less demanding and that was providing a similar kind of information. This brought me to the Critical Swim Speed (CSS) test that is used by SwimSmooth. You can find further information on the swimsmooth website but during this test you're basically swimming a 400m and 200m all-out and based on your result, your critical swim speed is calculated. Your CSS is representing the pace that you should be able to hold for 1500m (given the right training of course) and you therefore come to the same result as you get after your 30min test.
I have now combined the best of the 2 tests and calculated the different paces based on the CSS results instead of the 30minute test result, but still providing the matrix with training intensities.


A perfect tool to be used to ensure you're swimming with the right pace is a metronome. You can set this metronome to the time you need to swim per 25m and the tool will generate a beep when you're supposed to hit the wall after 25 or 50meter. It is a great help to pace yourself correctly. A good tool to be used is the Finis Tempo trainer Pro. Further info about the Finis Tempo Trainer Pro can be found here.

if you would like to receive the excel templates included in this post.


Contact Me