Lactate Threshold Field Test Protocol

30 Minute Protocol

This is a thirty minute field test protocol used to determine your “threshold power” or “threshold heartrate”.  Knowing your threshold heartrate will help you both plan workouts as well as measure progress in your training.

Field Test Warmup

(Why you should warmup before testing, training and racing, Sample warmups depending on your fitness level)

10 Minutes easy riding in middle chainring, 10 minutes…just easy spinning, get your legs loose, get your mind loose.
30 second spin up to 100 rpms, recover for 2-3 minutes, repeat once…effort should be light to moderate, easy gears.

30 second effort recover 2-3 minutes, repeat once. 5 minutes easy spinning  after that last hard effort and finish within about 5 minutes of the race start.

  • The 30 minute TT begins.
  • At 10 minutes into the test, hit the ‘Lap’ button on your heart rate monitor, to get the average heart rate over the final 20 minutes of the test.
  • The average for the final 20 minutes is your Lactate Threshold or LT.
  • You should finish knowing you gave it everything you had.
  • 15 minutes easy cool down.

Now you can do some simple math to determine HR training zones, either relative to your LTHR, or as a percentage. These zones are not hard and fast. Some authors recommend taking an additional 3-5% off of these zones for a 30minute time trial. You can do a 60 minute time trial taking your average HR for the last 30 minutes to get a more accurate lactate threshold heart rate


Calculating your Heart Rate Zones
Zone % LTHR Easy Math
Zone 1 (Recovery Zone) 65-85% < LTHR – 35 beats
Zone 2 (Extensive Endurance) 85-90% 25 – 35 beats below LTHR
Zone 3 (Intensive Endurance) 90-95% 15 beats below LTHR up to LTHR
Zone 4 -5a (Lactate Threshold 95-102% Tested LTHR from time trial
Zone 5b/5c (Power Training)   102-110% 5-10 beats above LTHR

Using the Training Zones

Now that you know your training zones, what do you do with them? Workout, of course! Any training that should be working on your aerobic base needs to be done in zones 1-2, no higher.

Training in zones 3-5 begins to recruit anaerobic or fast-twitch fibers which detracts from the building and training of your oxidative pathways.

Training in zones 4 and above is needed in order to create speed, improve lactate clearance and increase the amount of time near your lactate threshold at which you can

Please send comments/corrections to coach AT steelcityendurance DOT com


References:  Triathlete’s Training Bible, Joe Friel; D3 Multisport, Mike Ricci

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