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Setting Your Swim Training Zones

This article goes through how to set-up your Swimming training zones based off your CSS (Critical Swim Speed).

CSS Test

First you will need to complete an CSS test, which is two tests consisting off a 200 meters effort and a 400 meters effort. The CSS test take less than an 40 minutes, the protocol used in the BCA training plans is below.


100 m @ Z1/2 w/ 5 secs rest + (FS = Freestyle)

050 m @ Z1/2 w/ 5 secs rest + (PU = Pull (buoy between legs))

050 m @ Z1/2 w/ 5 secs rest + (KB = Kickboard (only legs))

050 m @ Z1/2 w/ 5 secs rest (FS = Freestyle)

Rest 30-60 seconds

Main Set

200 meters @ max effort

Rest 3 minutes

400 meters @ paced max effort

Cool Down

200 meter @ cool down using any stroke you wish in zone 1/2

CSS Zones

Your CSS is your 400 meters swim minus (-) your 200 meters swim divided (/) by 2.


200m = 3:16 mins/100m

400m = 6:49 mins /100m

CSS = 6:49 - 3:16 = 3:33/2

CSS = 1:46 mins/100m

The below table shows the training zone ranges for swim paces. Within BCA training plans you receive an excel document (within the link to the training guides) which you can use to calculate your CSS and zones based of the below.



Low (seconds)

High (seconds)



+ 15 secs

+ 19 secs



+ 10 secs

+ 14 secs



+ 5 secs

+ 9 secs



CSS pace

+ 4 secs



- 5 secs

- 9 secs

Table 1: Swim Pace Zones

Setting up Zones

Once you know your CSS go to your settings in TrainingPeaks by clicking on your name in the top right of your TrainingPeaks calendar. Then along the left hand side of the setting click 'Zones', you will then see 'Default Heart Rate'.

Scroll down till you see Speed/Pace. Under this click the drop down menu in 'Add Activity', click swim, then click add on the right.

Once you have done this you will see the below appear. Next, simply input your threshold (or CSS) click 'Add Zone' then fill in your training zones based of the tables above or the BCA excel spreadsheet provided in training plans.

When you have finished filling in your zones click 'Save and Close' in the bottom right.

If you have any questions please let BCA know.


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