November 13th I failed 10 second into the 339 watt interval. Today I completed the 339 watt interval and failed 8 seconds into the 353 watt. November 13th TR calculated my ftp as 239, today it said 228. How is this possible?
Ignore time and steps. They kinda matter, but the actual calculation of the FTP is based upon your best 1-minute power within the entire test. It takes that value time 0.75 to estimate the FTP.
- So, if there are variations in your actual 1-minute power between the tests, that will be what matters.
- Actually reaching any given point in the test only matters if you are meeting the prescribed power OR exceeding the prior 1-min power average peak (even if it’s lower than the new power target).
It would help if we could get a link to both of your ramp tests, via a web address on your TR web page, and you account will need to be public for that to work. If you want to keep the account private, a screen shot of each test may be helpful.
Short of that, an email to TR may be a good way to go as well.
Thx Chad, I checked my data, I see for the last 2 intervals that I completed that power is up to 50 watts lower then the target power of the interval. Makes no sense to me because my trainer is in ERG mode but it explains the test result based on the 1 minute power explanation that you gave.
Depending on your trainer, and any cadence drop you may have been experiencing, the trainer may not be able to adjust fast enough to hold the prescribed power target.
It’s also possible (again for some trainers) to hit a wheel speed and power combination that no longer allows it to add enough resistance. That is called a wattage ceiling and happens with some trainers.
Or it could be your trainer checked out and stopped ramping you for some reason. My trainer’s bluetooth connection had a wierd blip the other day and when the interval ended, trainerroad was still calling for the target power. Not sure if it was a trainerroad or trainer issue, but had to switch connections. Oddly, trainerroad rolled back their recent release shortly after.