Trainer vs Outdoors

Blindside

I hate the trainer.....

My FTP via the 20 min test on Trainer Rd using the trainer is 245 Watts yet when I am outside, with air flowing, something else to focus on, people to compete with - my latest Garmin 20 min average power number is 343 Watts - and I wasn't focusing on hitting higher numbers or battering myself. It was just a 3hr ride out with friends on undulating terrain.

Can any of the experienced heads please let me know how these 2 figures correlate? Can 20 min average Watts on a hilly/undulating outdoor session be useful to determine FTP? When on my trainer, I just cannot get near the numbers I regularly see outside even just on my longer Z2 rides. I don't know if that is mental weakness (very likely), overheating, boredom etc or it's more accurate than outdoors? or do the numbers of a flatter cycle not necessarily correlate with those from a hilly one?

The weather has improved here now and so the motivation to be on the trainer is almost nil.  I just don't want to waste the benefits of training with power but 245 Watts does not seem relevant outside and of course my IM will not be on a trainer.

I've read on here somewhere that it's common for outside FTP to be higher than from the trainer but mine (OK not FTP bit average 20 min power) seems to be quite different.

We live in a hilly area (on the edge of Peak District), my IM is supposedly a hilly/technical course so there isn't much flats.

cheers

 

Shaughn Simmons

The key here is to pick one baseline of measure and stay consistent with it.

If you are going to be training outside, do a 5/20 test outside.  Go as hard as you can for 5' spin easy for 10' then as hard as you can for 20' and take 95% of that 20' Norm Power result (not average power) as your outside FTP baseline.  Make sure you do the 5' test first laying it all out there, otherwise you will overstate your results on the 20' test. 

Stay consistent training against that baseline, incorporating your training plan/zones/interval work etc.

Forget about the Trainer Road data, it simply is not comparable to your outside test/conditions/etc., for training purposes outside.

SS

Chris Ciannella

It sounds like you are like me - indoor FTP test ADD. So, I'd take you outdoor FTP, as SS suggested to calculate, and start with that on your indoor trainer. My guess is, you will have to tweak down to get the right number for indoor purposes.

I'm probably the minority here, but I stopped doing FTP tests - I just hate doing FTP tests on the trainer, I can't (maybe don't) focus for 2o minutes. However, I know my FTP without doing the specific test. All my FTP indoor work is done either on a ladder basis: 6 min, 7 min, 8 min, 8 min, 7 min, 6 min with 4 minutes of rest inbetween or I do 5 5 min intervals all at FTP with a minute or 2 rest in between. By doing these workouts, I can fine tune my FTP and get a very good sense of it without doing the official FTP test. My outside FTP is higher.

Don't give-up on the indoor trainer - you can get some very solid WO's done that would be very hard to replicate outdoors

Blindside

Thanks for these comments, much appreciated. I "enjoy" the trainer for really focused workouts, maybe similar to your point Chris. It's good for the winter months, when it's cold and dark outside and you want to just get your WO done in a really efficient manner. I just really struggle with the FTP test itself. I've done 1 good FTP test and failed miserably on 4 or 5 other attempts.

I've just found the NP option on my Garmin so I'll use that for an outdoor test next.

William Jenks

100 watts difference is Wayyyyy out of line with the normal indoor/outdoor thing. I'm not sure it's impossible, but boy, that's huge. Have you tried doing any =15 minute segments indoor on your trainer over 300W? (I assume you are using the same power meter; please let us know if not.) Something like 10% difference inside to outside is a lot more common, whether it's higher inside or outside. You're looking at a 50% difference. Either there is something mechanical to fix or you're an outlier on having a hard time indoors. I am assuming that the indoors test was done in reasonable conditions and not a completely closed room with no fans and it being 90 degrees. :-)

Can you give us an idea of what the 245 and 345 W figures are in W/kg?

Blindside

I'm 104kgs and a broad 6ft 3 (plenty of wind resistance!). I use the Powertap pedals all the time.

I think it's an error more than a genuine difference, perhaps the truth is somewhere in between. Just wanting to make the most of the training by getting an accurate idea of where I am.

I feel that I overheat indoors even with the patio doors open when on the trainer (no fan). I haven't tried doing anythjng like you describe on the trainer, I enjoyed some interval sessions but as soon as I could I went outdoors.

I don't know whether hilly terrain makes a difference and shouldn't be compared to a "flat" measurement?

Joe Matchette

Posted By Rob H on 17 May 2016 04:52 PM


I'm 104kgs and a broad 6ft 3 (plenty of wind resistance!). I use the Powertap pedals all the time.

.................

I feel that I overheat indoors even with the patio doors open when on the trainer (no fan). I haven't tried doing anythjng like you describe on the trainer, I enjoyed some interval sessions but as soon as I could I went outdoors.

................

Rob - recommend you get yourself one (or two!) of these bad boys.  -- http://smile.amazon.com/Stanley-655704-Velocity-Blower-Yellow/dp/B006O6FA22?ie=UTF8&keywords=floor fan&qid=1463623118&ref_=sr_1_13&sr=8-13 -- they move A LOT of air.

Scott Giljum

I have a difference between indoor and outdoor as well, but 100 watts is as William said, way out of the bounds of expected/possible. Maybe a calibration issue? Either way, I would also agree with SS and crew that doing a legit test outside would be best. If you are doing the longer rides, you can start to dial in power numbers from those rides as well.

Blindside

Thanks for all the input, it's a great learning experience. There I was thinking that I was a BEAST!

Coach P answered my question too and here's what he said:

Rob, thanks for asking. There is always variance with FTP...in this case:

(1) The difference between indoor and outdoor FTP...usually 10%. So if I am 275 outside I am 250 inside.

(2) Hills inflate your FTP. So if I am 275 outside on the hills, I am probably closer to 250 inside.

Connecting 1 and 2 above, it's more likely that your 330 on hills, which puts you closer to 3o0 flats...and 275 inside. That sounds fairly reasonable to me for someone who hates the trainer. That said, go ahead and crush yourself on the hills...just plan on riding STEADY on the Saturday sessions so you get time to practice what it means to flatten a hill (smooth power effort).

Here is an article on the flattening approach: https://www.endurancenation.us/blog...he-en-way/

Since we are in season, your outdoor numbers rule the roost. Keep up the good work!