Endure IQ Critical Swim Speed Calculator

Jun 03, 2024

I talk a lot about physiological profiling, and how getting tested in an exercise physiology laboratory can be really helpful for refining your training. However, I also know that many athletes do not have access to exercise physiology labs for this testing.

Accordingly, I’ve put together a couple of calculators on the Endure IQ website that you can use to get decent estimates of things like intensity thresholds using easy-to-access field test data.

In this section we are going to talk about the critical swim speed calculator. I’ll walk you through how to perform the field tests to get the necessary data. But we also include calculators for fat max/lactate thresholds, functional thresholds power, and critical running speed.

Field test estimate of critical swim speed

The Critical Swim Speed calculator needs to best paced time trials over 200 m and 400 m. This can be done within the same session, so it’s important to have a good warm up before the first-time trial and also ensure you are as well recovered as possible before the second. I recommend you incorporate the two-time trials into a swimming session of around 2200. An example swim session could be:

400 choice (+20 sec recovery)

8 x 25 as 12.5 m FAST (explosive off the walls), 12.5 m cruise (+20 sec recovery)
4 x 50 descend 1-4, each 1 get faster (last rep should be at about 200 m race
pace) (+20 sec recovery)

Time Trial: 1 x 400 m at best possible pace* (+90 sec recovery)
*looking for good pacing
1 x 400+* (can be less or more) choice swimming, super easy recovery
*take as much time as you need to recovery here

Time Trial: 1 x 200 m at best possible pace* (+90 sec recovery)
*looking for good pacing again

400 as 200 kick, 200 swim

Once you have those two times head over to the Endure IQ calculator and enter those values to get your critical swimming speed.


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