How to complete a Critical Swim Speed (CSS) test
You can complete this testing protocol in any indoor swimming facility, but you should aim to find a quiet time when you will not be impacted by other swimmers. This is a maximal test and therefore the limiting factors should be your form and fitness, not other traffic in your lane.
- Perform a warmup, progressively bringing your heart rate. Use a warm-up that you are familiar with and would be your normal preparation prior to a structured swim set.
- Swim 400m at a pace you can sustain for the distance. Capture your time, which is probably easiest done using your swim watch if you do not have a poolside assistant. Remember, your goal is to swim at the maximum pace you can sustain for 400m. Pace judgement is key to getting the best from this test.
- Take 5 to 10 minutes to actively recover. Swim some easy lengths to help flush lactate from your muscles and being your heart rate back down to z2. The amount of time you take for this recovery is not too important, but it is helpful to keep a record of it so that you can reproduce the same conditions in subsequent tests.
- Next, swim 200m as hard as you can and record your time again. Again, your goal is to swim at the maximum pace you can sustain for 200m.
- Check that you swam the 200m at a faster time per 100m than the 400m. This should always be the case because it’s a shorter distance, but in some rare situations the 400m is done so fast, and the recovery so short, that the subsequent 200m is not swam at a maximal pace relative to the distance. This is essential in order to calculate your CSS pace. In fact the Swim Pace App will reject your times if the 200m swim is not faster paced than the 400m.
- End with a cool down. It can also be useful to do some light stretching to aid in recovery.
What’s next
Now that you have your times for the 400m and 200m swims, you are all set to use the CSS Swim Calc App to calculate your CSS, record the details, track your progress from your last test, and vitally important set the in app reminder for your next test.
Good Luck and Happy Swimming