So, after doing a 20 min road FTP test and a 20 min trainer FTP test there is a significant difference.
On road results 257 watts for the 20 minutes meaning a estimate FTP of 244 Watts. On trainer results 222 watts for the 20 minutes meaning a estimate FTP of 210 Watts.
Firstly I need to work out why there is such a difference, but at the moment I am trying to work out how to best management that in the PMC in WKO+.
If I use trainer FTP across the board the TSS for road rides will be way to high and vice versa for trainer rides if I use the road FTP.
At the moment my more intense sessions are all trainer based and the only road rides will be longer weekend base building type rides.
Just curious, what were the other metric variations like - most specifically RPE and HR? I'm guessing you smashed it for both tests. Cadence, warmup, perceived levels of fatigue before starting, etc., would all also be interesting. I have heard though that the open road is more conducive to putting out power.
Btw I know there are formulas for deriving FTP from a 20min tests but Friel recommends doing a 30min test for a better SWAG, considering that the make it or break it "best effort" is probably only attainable during an hour TT or race when the chips are all in. I'm not advocating in any way as a bona fide replacement but it is one of the options out there.
RPE pretty similar, possibly a bit higher on the trainer.
Heart rate, 172 ave - 178 peak on the road, 170 ave 181 peak on the trainer.
I tried to consciously start a little easier on the trainer test as generally on these 20 minute tests I go out too hard. I negative split the 20 min power on the trainer building to the end on the road I went out harder and died a death of 1000 cuts through the 20 minutes.
There may be a few watts in the execution, will redo trainer test in 4 weeks and hopefully can go better then with some fitness and execution improvements.
Have been thinking about hacking it to increase inertia, but not game to in case I mess it up
I've seen folks report that their trainer FTP is significantly below outdoor FTP when using low-inertia trainers - and this looks like one. I've also seen folks report that they adapt after a few weeks and don't pay further attention to it.
You just give it a couple of weeks of working out on the trainer and test again.
Trainers suck, man. I absolutely die trying to do 10 mins at 90% on the trainer, to the point where I don't even try anymore, whereas I can knock out an hour at 90% on the road and keep right on going without even really thinking about it a ton.
Trainers just suck. Rollers too. Indoors sucks. That's the way it is.
I am not so worried about the difference in power produced, more so its affect on the PMC.
Today I did a hard group ride, with my FTP set at 210 Watts as per trainer FTP.
Ride was 3:41 long, average 161 watts with a normalised power of 200 watts(IF 0.956) and a VI of 1.24. That equates to a TSS of 336 which just seems too high.
I know it was a hard ride and I am absolutely spent from it but if I use a FTP of 244 as per previous road test the TSS drops to approx. 250.
Should I override the TSS? Do I have to keep track of a trainer FTP and a road FTP?
Originally Posted by Toolish I am not so worried about the difference in power produced, more so its affect on the PMC.
Today I did a hard group ride, with my FTP set at 210 Watts as per trainer FTP.
Ride was 3:41 long, average 161 watts with a normalised power of 200 watts(IF 0.956) and a VI of 1.24. That equates to a TSS of 336 which just seems too high.
I know it was a hard ride and I am absolutely spent from it but if I use a FTP of 244 as per previous road test the TSS drops to approx. 250.
Should I override the TSS? Do I have to keep track of a trainer FTP and a road FTP?
IF of 0.82 seems more plausible for a tough 3.5hr ride with that VI. What you could do is create a separate WKO athlete for your trainer workouts only, with an FTP of 210. Then duplicate the same trainer workouts in your regular WKO athlete profile with FTP of 244 but override the TSS there with the one from the Trainer Athlete. A bit of work but easily done.
I think you simply accept the lower TSS and recognise that's an element of the composition of your training that explains why CTL/ATL/TSB curves have the shapes they do, and where possible look to narrow the performance gap.
For me interpreting the PMC is less about precise absolute values and more about the trend lines.
Originally Posted by Alex Simmons I think you simply accept the lower TSS and recognise that's an element of the composition of your training that explains why CTL/ATL/TSB curves have the shapes they do, and where possible look to narrow the performance gap.
For me interpreting the PMC is less about precise absolute values and more about the trend lines.
I couldn't agree more. Trying to nail FTP/PMC to accuracy that's beyond that of the Powermeter - and day-to-day fluctuations of FTP is a fool's errand.
