Lactate Test #3: Moving in the right direction

July 10, 2018  ●  5-minute read

Last week, I did my third lactate test of the season. As planned after my second test, I wanted to minimize glycogen depletion in the anaerobic portion, so I split the test into two parts. I did the aerobic part on July 2nd and the anaerobic on July 3rd.

Since my test on May 21st, I’ve started local muscular endurance (LME) training. I worried that starting LME would push my curve up and left, but that hasn’t happened. In fact, my curve is now more aerobic (having moved down and right). This is true for both pace and heart rate. My anaerobic capacity is slightly reduced, but still strong.

My aerobic threshold climb rate (at ~2 mM of lactate) has moved from ~1,000 to ~1,075 meters per hour. By heart rate, my AeT is almost restored, having moved up from 169 to 177 bpm. My anaerobic capacity has declined from 14.5 to 13.6 mM.1

A graph of results for my July 2nd lactate test
In early July, I completed my third lactate capacity test of the season. The results are promising, showing a shift in the curve down and to the right. (The dark red line is the most recent test. The other lines, also red, fade as the date of the test gets older.)

What does this lactate test show?

In my last test, I worried about how glycolytic I was at low heart rates. It’s unusual for me to approach ~2 mM of lactate at heart rates in the 160s. When I’m in race shape, ~2 mM is usually in the low-180s. To compensate, I cut back on anaerobic development and increased the speed of my aerobic capacity workouts.

My curve has started to move down and right, so it appears that those were good decisions. My aerobic threshold heart rate (AeT HR) is only six beats lower than usual. Things are moving in the right direction.

Another positive result is a mild increase in anaerobic power. The anaerobic capacity part of this test was at the same pace as the second test: 2,400 mhr. But I was able to hold that pace 17 seconds longer (73″ versus 90″). In my next test, I’ll increase the speed to keep the interval between 45″ and 90″.2

What training led to this shift?

Here’s a breakdown of the training that I’ve done between my second and third lactate tests:

  • Modes: max strength, hill sprints, fasted sessions, super easy volume, faster aerobic work, local muscular endurance
  • Volume versus intensity:
    • 99.7% <= of AeT HR (versus 98.7% before my second test);
    • ~64% <= 80% of AeT HR (versus ~74%).
  • Specificity:
    • ~25% of training time was on (roller) skis (versus ~36%);
    • ~97% was weight-bearing (versus ~99%).
Three graphs that show recent training distribution by heart rate zone
Training Distribution by Heart Rate Zone: The left-most graph is my training distribution for last season (2017/2018). The middle graph is the distribution for the current season (2018/2019). The right-most graph is the distribution between my previous test (on May 21st) up to the day before my most recent test (on July 2nd).
Three graphs showing my recent training distribution by trainiing mode
Training Distribution by Training Mode: The left-most graph is my training distribution for last season (2017/2018). The middle graph is the distribution for the current season (2018/2019). The right-most graph is the distribution between my previous test (on May 21st) up to the day before my most recent test (on July 2nd).

How does this influence the next training phase?

My lactate curve has shifted down and right as I’d hoped. Now that things are moving in the right direction, I’m going to stick to my original training plan.

Over the next six weeks, my priorities are

  • Maintain anaerobic capacity
    I’ve finished the anaerobic capacity development phase. Now I’ll maintain anaerobic capacity with a short sprint workout every seven to ten days. I’ve had great results preceding max strength workouts with a sprint warm up, so I’ll continue combining the two into one workout.

  • Continue to extend and speed up my aerobic capacity workouts
    Speeding up my aerobic capacity workouts has helped. It’s put that progression back on track. Spot tests during workouts have shown declining lactate levels at comparable paces.

  • Continue progressing my local muscular endurance work
    I worried that LME work would make me more anaerobic, but that’s not the case. In fact, judging by my lactate after LME workouts, the opposite has happened. As the demands of LME workouts have increased, heart rate has increased, but post-workout lactate has fallen. That’s a clear sign of aerobic improvement. And now that sprint work is in maintenance mode, I can increase the frequency of LME work from once per week to two.

  • Increase proportionate roller skiing volume
    Since my previous test, my time on skis fell from ~36% of training volume to ~25%. This is due to the arrival of summer and fewer opportunities to get on snow. Still, I’d like to maintain a ~30% minimum, so I’ll need to increase my time on roller skis.

  • Increase the pace of the next anaerobic capacity test
    To test anaerobic capacity in an Olbrecht-style lactate test, you need a maximal effort that lasts between 45 and 90 seconds. As mentioned above, I was able to hold the target pace for 90″, so I’ll need to increase the speed next time. Bumping up the pace from 2,400 to 3,000 mhr should cause a noticeable drop in sustainable duration.


  1. In an Olbrecht-style lactate test, the aerobic and anaerobic capacities are not measured in absolute terms (of VO2max and Lamax, respectively.) The test measures their strengths relative to one another. If one capacity weakens, the other will appear stronger, and vice versa. As such, there are 13 different ways that a lactate curve can shift, so some skilled interpretation is necessary. Performance factors, both inside and outside the test, need to be considered. 

  2. Increases in anaerobic power are often explained by increases in anaerobic capacity. But the opposite is true: an increase in aerobic capacity leads to an increase in anaerobic power. As aerobic capacity increases, the aerobic system can absorb more lactate. With more lactate absorbed, blood lactate is lower for a given intensity. With lower blood lactate, higher intensities can be maintained for longer. Thus anaerobic power–measured by the maximum duration of a near maximal effort–increases alongside increases in aerobic capacity. This phenomenon is counter-intuitive and often misunderstood. The confusion is the birthplace of HIIT training and its ilk. High intensity is necessary for all athletes, but if used in isolation, HIIT training will destroy everything an athlete has built
Posted in: endurance training