Saturday – 2 speed Lactate test and some thinking

Time for the 2 speed lactate test again. The protocol is simple.

  1. Do a thorough warming up
  2. Row a 1k “at 6k pace”
  3. Take 15 minutes active rest, measuring lactate at 1 and 3 minutes
  4. Row a full out 1k
  5. Row a cooling down, measuring lactate at 1, 3, 5 and 10 minutes.

Then you plot the 1 minute values against power.

I started with a 20 minute warming up:

Then I did the first 1k:

Pretty evenly paced. I measured 5.4 mmol/L  of lactate after 1 minute and 4.5 mmol/L after 3 minutes. I paddled until 15 minutes was gone, at roughly 150-160W pace.

Then I did the second 1k:

I knew this wasn’t going to be a very fast 1k, so after 10 hard strokes at the start, I settled for 300W, then tried to crank it up with 500m to go.

So here is the result (lactate in mmol/L).

Measurement Lactate Power
1 min 5.4 270
3 min 4.5
1 min 6.1 315
3 min 8.1
5 min 7.2
10 min 4.3

The droplet of blood after 1 minute after the full out 1k was a little smaller than normal. I think the measurement was OK. It seems the lactate concentration in the muscle was just much higher and it took time to flush out the lactate. This would explain the higher value after 3 minutes.

Here is the graph of all 2 speed tests I had done in the past 12 months:


The chart looks like a game of Mikado (or pick-up sticks) and it is hard to understand what is going on. I have been rereading on Lactate, especially this article. I picked up my old simple numerical model and tried to model the recent three series of lactate step tests I did in September.


Not an ideal fit but it is interesting to look at the parameters.

Nov ’15 Sep ’16
Pthreshold 200 195 W
beta 0.1 0.15
C_La rest 0.7 1.5 mmol/L
V_La_max 0.1 0.2 mmol/L/s

Pthreshold is the threshold Power. The parameter “beta” is a parameter which governs lactate usage as fuel in the aerobic pathway (higher values mean more lactate can be used as fuel during aerobic exercise).  “C_La_rest” is the rest value of lactate (which I measured today), and “V_La_max” is a parameter which governs how fast lactate is produced once you are above the threshold. So the hypothesis is that my threshold power has shifted to the left (bad), but I am better at burning lactate during aerobic exercise. At the same time, I have become better at producing a lot of lactate when above the threshold.

The model should be taken with a very big grain of salt. It’s all very crude and simplified at the moment. Take it as an illustration of my current understanding of lactate “science”. Instead of looking at individual test results, you have to build a model of how blood lactate is generated and used. In “Olbrecht” language, my Aerobic Capacity has slightly decreased, but my Anaerobic Capacity has improved a lot.

Now, if I knew what that means in terms of race performance, and how to use the result to fine tune my training plan … that would be great.


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