Aaron,
Those data points showing high lactate at 190w and 200w and likely at 210w are aberrant. There is essentially no condition where you would be at 1.2-1.3 mM (as expected for low power compared to FTP) then spike to 4mM and then go back down again while increasing wattage.
Looking forward, consider the following to improve your lactate test results and usefulness of the data:
Step zero: Establish how close the power meter you use outdoors relates to the indoor unit. No two power meters will ever match perfectly, but you should have an idea of how close they are.
Step one: Revisit your testing methods and procedures. How you are taking the sample and ensuring that a sample is not contaminated. Am assuming you are taking your own samples by getting off the bike? That is fine. Just take the sample and do the point tests the same way each time. If you have a helper, ensure they are as consistent as possible.
In the future, if you see an aberrant data point, either ignore it and keep going, or resample.
Step two: Repeat your test. You can consider a different protocol and starting point. My feeling is you are starting too low and taking far too many samples. 10w steps are fine when you get close to the LT1, but poking your ears or fingers from 150 to say 220 watts with an FTP of 300w is a lot of sticks for low utility.
With an outdoor FTP of 300w, your LT1 I going to be much, much higher than 150w. I would warm up, establish baseline and then take samples every 20-25w. See where your likely LT1 is. Come back a few days or a couple weeks later and then do smaller steps in the LT1 area to lock it down.
Something like this: Warm up 20 min. Start test. Samples at 150-175-200-225 then 230-240-250-260-270-280-290-300-310-320
That is still a lot of sticks. But next test you can adjust as you’ll have a good idea where your LT1 is.
LT1 will be where you see the consistent upward inflection start. With additional training it should shift higher and closer to your FTP. Note - I prefer MLSS to FTP when talking about lactate testing.
For LT1 estimation, I typically ride at least 5 min at each power level where a sample is going to be taken. MLSS is a completely different protocol. There are notes up thread should you wish to do that type of testing.
Finally, if you have a true FTP of 300w outside and 210w inside feels like very hard work, something is wrong. There are a few things that could be happening there and you’ll want to investigate:
First is that the power meters are giving you very different data outside vs inside. Please check this as it’s important to your training.
Second is you might be overheating and having a heightened sense of high RPE indoors. There are tons of threads on heat and indoor training and perception of indoor training feeling much harder.
Third is you might have an RPE to Physiology disconnect. Your perception is real, but it’s mental and not physical. This is one place where lactate measurements can help an athlete improve. If your legs are good (low lactate measure at a certain power) but your brain is screaming, you can work on the brain part.
Despite what coaches will tell you, not all athletes have well calibrated RPE meter built into their brains. many do but some do not.
TL;DR - Establish the relationship of your outdoor power measurement to your indoor power measurement. Repeat the lactate test trying to be as consistent as possible with sampling. Determine the cause of your indoor vs outdoor RPE disconnect.
Very best luck,
Darth