Cycling Lactate Threshold Heart Rate (LTHR) and Functional Threshold Power (FTP) Test


This test is important to see where you are in terms of what intensity to use during the workouts I’ve described.  Using the correct FTP and LTHR and setting those numbers in your cycle computer and TrainingPeaks will correctly calculate your CTL, ATL, and TSB so you can gain insight into your fitness and progress.

You’ll need a heart rate monitor and/or power meter with a cycling computer that can calculate the average heart rate or average power.

Test Execution

Here are some tips for the best possible results for your test execution

  • Warm-up for 20-30 minutes, at the end of the warm-up, do a 5 min hard effort (95% of the previous test).  Recover for 5 minutes with easy spinning before starting the test.  Keep pedaling into the recovery.
  • The test should be hard, drooling from the mouth, nose dripping, sweating, breathing heavy, your best time trial hard.
  • There should be no breaks or coasting during the test.  You should be on the gas the entire time.  Any coasting or reduction in the effort will affect the test results especially the power test.
  • Picking a course that allows this effort for the 20-30 min test is critical to getting your best result.  Do not use a course with any downhills, stop light/signs that will cause you to stop or slow down.  Using a trainer will provide the most controlled environment, but it’s also the hardest way to do the test.  If you can’t find a proper course then use an indoor trainer.
  • Make sure that you are well-fueled, hydrated and rested before doing the test. The last meal should be 1.5-2hrs earlier and digested before starting.

Lactic Threshold Heart Rate (LTHR) Test

If you are training using an HR Monitor you should follow this test.

After your warmup press the Lap button on your device.  Keep a cadence around 85-90 rpm.  Don’t forget you have to pace yourself for 30 minutes, so don’t go out too hard, but hard enough to push yourself.  This is a 30 min time trial.  After 10 min or so you’ll start to feel the burn in your legs and your breathing should be heavy.  You can only talk 2-3 words at a time.  After 30 min, hit the lap function again to stop the clock. Get your average heart rate.

The average Heart Rate is your LTHR.  Update your training peaks account Heart Rate zone and device zones with your new LTHR value.

Why take only the last 20 min avg of the test?  Cardiac drift.  Your heart rate takes a while to get up to speed with your effort, usually 5-10 min.  To accommodate this, you start your test early, to get your heart rate up near the threshold and give a better indication of the LTHR.

Functional Threshold Power (FTP) Test

For Power Meter users only.  If you are only training by HR you can skip this test.

The FTP test is about the same as the LTHR test.  However, instead of a 30 min test and taking the last 20 min HR avg, the test is 20 min and you take the avg watts for the 20 min.  To get your Functional Threshold Power (FTP) requires a little math.  Your FTP is 95% of your 20 min power avg (avg power x .95)  For the avg power of 300w, the math looks like this. (300 x .95)=285.

Update your TrainingPeaks account power zone and device zones with your new FTP value.

Your Zone and Power Levels

Now that you have your LTHR or FTP, you can get your training zones and power levels (if you are using a power meter).  Within our training plans, we reference the zones and levels.  Once you have your LTHR or FTP you can use my Zone Calculator to find your training zones and levels.

1 thought on “Cycling Lactate Threshold Heart Rate (LTHR) and Functional Threshold Power (FTP) Test

  1. […] Friel’s Heart rate zone calculator. If you have Training Peaks it’s right in there.  Here is another good online one that you can plug numbers into and have your […]

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