Based on feedback from Boris and Tom, I dialed back the steady state power from th 190W that I targeted last week to 180W this weekend. The goal was to get some meters in the bank and do another experiment to see what my lactate levels do over long pieces.
- 4×20′ / 1′ rest (actually about 1:15 or so by the time I did the lactate test and had a slug of water)
- Target rate: 18 to 19 spm
- Target power: 180W
- No HR cap, training to target power
- Lactate tests after each 20′ piece.
Very interesting results. Kind of depressing really. I backed off power by 10W and the saw very close to the same picture for HR and lactate.
Workout Summary – Sep 21, 2015
–_|_19268_|_80:00.0_|_02:04.6_|_181.1_|_18.3_|_142.2_|_ 69.6% _|_13.2_|_09.9
01_|_04821_|_20:00.0_|_02:04.4_|_181.6_|_18.2_|_125.3_|_ 57.7% _|_13.3_|_10.0_|_1.7
02_|_04818_|_20:00.0_|_02:04.5_|_181.2_|_18.1_|_138.7_|_ 67.2% _|_13.3_|_10.0_|_3.3
03_|_04816_|_20:00.0_|_02:04.6_|_180.9_|_18.1_|_149.2_|_ 74.6% _|_13.3_|_10.0_|_4.1
04_|_04813_|_20:00.0_|_02:04.7_|_180.7_|_18.9_|_155.0_|_ 78.7% _|_12.8_|_09.6_|_5.2
Compared to last week, my HR took a little longer to hit each band. And my lactate at 20 minutes was lower than last week (1.7 vs 2.3), by after 20 minutes, my HR and lactate just kept on rising and rising.
Now, this is really intriguing. Based on what I was doing the past couple of years, I would have enthusiastically embraced the 1.7 reading and kept my training power at 180W, because I wouldn’t have taken any more readings.
So, this these results are a bit counterintuitive because it is generally thought that a lactate reading below 2.0 after 20 minutes indicates that the power level is low enough that it will stay there for the duration of the training session. I am not sure what is going on, but I have a few ideas. Lactate accumulation can result from two causes.
- The ability to metabolize fat is low, therefore the transition from fat metabolism to glycogen metabolism occurs at a lower power than the training power. This causes the over production of pyruvate, which leads directly to lactate levels rising
- The ability to metabolize lactate is low, therefore lactate accumulation happens at a lower power level than expected.
Of these, the more plausible is number 1. If I have been habitually training at too high an intensity, then I have been bathing my muscles in lactate and that would provide plenty of stimulus to improve lactate metabolism. But, the same hypothesis, too high a training power, would definitely cause fat metabolism to shut down and not be developed and improved. I’ve become an anaerobe by doing my steady state at too high an intensity.
I did some digging and found a thread over on Rowing Illustrated which is on point.
A rower with a 380W 2K (roughly 6:30) did a 20′ lactate test at 185W and got a lactate reading of 11.1mmol/l. He finally ended up down at 155W with a 1.85 reading after 20 minutes.
Anyway, I think another shot at this with the power down at 170W next weekend is my next step.