To set your swim threshold pace in Training Peaks, we recommend a Critical Swim Speed test (CSS). This simple test gives you a good idea of your current fitness and can also be used to set your pace-based training zones for swimming.
After you've done a CSS swim test, use our online calculator to work out your current CSS swim pace (per 100).
The aim of a CSS test is to predict your current race pace for 1500 metres or yards. The beauty of the test is that you don't actually have to swim 1500.
To test your current CSS pace you need to swim a 400 and 200 Time Trial within the same session. Swim as hard as you can for both time trials, with around 5-10 minutes of active recovery in between. Ideally, get a friend or coach to time you and record your 100 splits and strokes per minute. Failing that, simply record the 400 and 200 times yourself.
We don't include CSS tests in the training plans, but we recommend you do one every 8 weeks (during a recovery week). This will give you an idea of your current fitness and also allows you to update your training zones.