Your Lactate Threshold or LT Pace is a great training tool to use in your running to help you train your body to become a faster and more economical runner. I use LT as a gauge for athletes in several different run sessions including one of my favorites the Swing Pace Run Workout. If you don’t know your LT or haven’t had a test completed, here is an easy workout to do to calculate your LT pace. Tracking your LT allows you to access all training intensities. This is the single biggest determinant to quantify your potential training and race paces.
Schedule this workout every 3 weeks during the early season and every 4 to 6 weeks during your race season. Fitness fluctuates with stress, time off, injuries and over training. An objective evaluation allows you to recalibrate your current levels.
Keep in mind that LT varies with each individual. The factors depend upon current run fitness; intensity of previous training and; motivation.
Keeping this in mind, maintaining a steady pace at LT may vary between 20 min to 80 min depending upon the factors noted. Here’s why…
There is a shift of aerobic to anaerobic metabolism when you are testing LT. The clearing mechanism that is overloaded with muscle acidity (primarily legs) cannot keep up with the intensity. Consequently the physical signals at LT are as follows:
- Elevated and deep breathing rate
- Heavy legs then heavy body
- Heart rate is high
- Concentration is acute
- Pace falls off
LT Progressive Set:
12 x 2.5 min hard to very hard run. If you are a beginning runner, try a set of 8 x 2.5 min and for a seasoned runner a set of 20 x 2.5 min.
The rest interval after each repeat is 30 seconds. During the rest interval, keep jogging or walking slowly and note the distance of each repeat.
During the 2.5 minute segments you should aim to run them at a pace you can hold for the entire duration. This will take a bit of guesswork so don’t run too quickly at the outset.
Once completed take your average pace of the intervals and you’ll have your estimated LT pace. If you do the workout correctly, the paces should be close!
Please keep in mind that humidity and temperature will zap your progression. Your heart is under siege in hot and humid conditions so this is not an ideal environment to test your LT pace. Also, this workout can be done indoors on a treadmill at a 1% grade as an alternative to outdoors if the conditions aren’t ideal.
As you progress in your season and re-test your LT pace, you can also adjust the workout according to your fitness level. Shortening the rest interval to under 30 seconds and lengthening the repeat time or distance can be the two controlling variables as your progress. Try progressing from 2.5 to 5 minute segments. For example try 11 x 3 min to 9 x 4 min to 8 x 5 min. The sweet spot on intervals for LT testing is generally the 3 to 5 min range. However, maintaining the same repeat length and set distance standardizes your test throughout the year.
These intervals can be a solid ladder that can parallel your fitness in the coming months and set you up for a successful run split in your next race. Lastly, the LT pace is darn hard and maintaining a pace 5 to 25% below this number is quite often the goal in Triathlon racing. Use LT as the barometer of discomfort to set your paces!