Although you could use one of the time-based field tests for swimming, it’s more common to use a distance-based time trial. For experienced swimmers, a 1,500-yard/meter time trial is used. For new or less experienced swimmers, a 1,000-yard/meter time trial can be used.
Pace is the most common metric used for swimming — and this time trial was designed by Joe Friel to find what has been termed your “T-pace,” or your FTPa for swimming (sFTPa). Now that heart rate monitors and power meters are available for swimming, you can also use the time trial to collect heart rate and/or power data during the time trial to find your LTHR and FTPw for swimming.
Time Trial Protocol
You should go into the test rested, not after a hard training day. Use the pool distance that you will be training in most of the time, such as a 25-yard short course pool or 50-meter long course pool. You can repeat this time trial throughout your training year to compare results over time.
The objective is to swim as fast as you can for the time trial distance. Avoid starting out too fast and then slowing. You want a consistent effort over the full time trial distance.
Warm up for 15-20 minutes with some short sprints and pickups to prepare your body for the time trial effort.
Swim the time trial distance at the fastest pace you can consistently maintain.
After you’re done, warm down for 10-20 minutes. When you get home, upload the workout to your TrainingPeaks training log. In your post-workout comments, record the conditions (water temperature, pool setting, etc.) and other contextual factors that impacted how you felt (sleep, eating, etc.).
Interpreting the Results for Pace (FTPa)
The average pace over the time trial distance is a good indication of your FTPa for swimming (also called T-pace or sFTPa).
For example, let’s say you swim a 1,500-yard time trial in a 25-yard short course pool in 20 minutes flat. Divide 20 minutes by 15 to get your pace per 100 yards. In this case, that pace is 1:20 per 100 yards. This is your swimming functional threshold pace (sFTPa). You can use the Alp Fitness swimming pace zones calculator to do the calculation.
Once you know your sFTPa, go to the section, “Setting Your Pace Zones,” to use that number to set your pace zones.
Interpreting the Results for Heart Rate (LTHR)
Take your average heart rate over the 1,500-yd/m time trial and multiply by .95. This is a good indication of your LTHR if you’re an experienced swimmer.
If you have less experience with swimming, choose one of the following coefficients based on your experience level:
- 92%: New or inexperienced in swimming
- 93%: Some experience in swimming
- 94%: Experienced in swimming
- 95%: Very experienced in swimming
Multiply the percentage in decimal form by your average heart rate for the time trial. This is a good indication of your LTHR for swimming.
For example, let’s say you have “some experience with swimming” and your average heart rate for the time trial was 165. Multiply 165 by .93 to get 153 as your LTHR for swimming.
Once you know your swimming LTHR, go to the section, “Setting Your Heart Rate Zones,” to use that number to set your heart rate zones.
Interpreting the Results for Power (sFTPw)
Take your average power over the 1,500-yd/m time trial and multiply by .95. This is a good indication of your FTPw for swimming (sFTPw) if you’re an experienced swimmer.
If you have less experience with swimming, choose one of the following coefficients based on your experience level:
- 92%: New or inexperienced in swimming
- 93%: Some experience in swimming
- 94%: Experienced in swimming
- 95%: Very experienced in swimming
Multiply the percentage in decimal form by your average power for the time trial. This is a good indication of your sFTPw.
For example, let’s say you are “experienced with swimming” and your average power for the time trial was 105. Multiply 105 by .94 to get 99 as your sFTPw.
Once you know your sFTPw, go to the section, “Setting Your Power Zones,” to use that number to set your power zones.
