It's off 20 minute power. It's accurate but could be based off a hammerfest road bike effort where you were out of the saddle hammering hills. Not sure I would want to use that for my triathlon based FTP. Honestly, let your premium membership lapse and spend that same amount on training peaks. Mucho better.

A bit ironically, I posted this this morning:

https://www.facebook.com/.../?type=3&theater

Thanks. So you think it just takes your best 20 minutes of last 6 weeks of riding?

Was wondering if it was some almagamation of all rides...for greater accuracy.

For tri I did a separate test in aero position that I will use for pacing but will prob update closer to event.

In what ways is TP better/more effective?

Why don't you just set your FTP in Strava...?

Yea, you can change the time window on Strava but you have to be careful with using "that number" for racing. Training Peaks can do the same thing but way more metrics on power breakdown and what buckets you are filling up across the time horizon. Run metrics are also pretty cool.

I have that set as well but saw this # the other day and was wondering where it was coming from/accuracy.

It is set, this is just giving an "estimated FTP" based on "historical" workouts, not sure what date range it is working with. And Andy is going to probably chastise me for saying this, but they are trying to do the same thing that mFTP is doing, at least from my general understanding.

From here: http://www.hunterallenpowerblog.com/...metrics-in-wko4.html
Modeled Functional Threshold Power (mFTP) mFTP is the model-derived highest power a rider can maintain in a quasi-steady-state without fatiguing. When power exceeds FTP, fatigue will occur much sooner; if power is just below FTP, it can be maintained much longer. FTP is the single most important physiological determinant of performance in events ranging from as short as a 3-kilometer pursuit to as long as a 3-week stage race.

You can read up on Functional Threshold Power here to better understand the concept.
How we use mFTP

• To measure the increase or decrease in FTP as based on modeled estimates, giving better insight into training effectiveness or ineffectiveness
• mFTP can support the accuracy of your FTP management system (testing, predicting…) and allow you to set zones based on percentages of FTP.
• mFTP can be used as the basis for numerous analytics in WKO4 to better help diagnose and prescribe workouts.

Analytics can supply answers. The focus of WKO4 and the new Power Duration Model is to supply coaches and athletes with new metrics and robust analytics to better determine training strategies and to better (and more quickly) measure their effectiveness.

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-Brad Williams
Website | Twitter: @BW_Tri |Instagram: @BW_Tri | Strava | Co-Founder & Coach at: KIS Coaching
Partnered with: Zoot Sports | Precision Fuel &Hydration | ISM

My Strava - for some reason - calculates my "estimated FTP" off my 10 min power. To top it off strava estimates my FTP to be 95 % of my 10-min power (which I believe is FAR off). Anyone else have Strava estimating FTP off 10-min power? I have a pretty clear idea of where my FTP is, so not to worried about this, but if possible it would be nice to alter the algorithm in my strava so it does not grossly overestimate my FTP.

For someone who is such a stickler for using words appropriately, I'm surprised to see you call this ironic.

It's not ironic in the slightest, it's coincidental.

How ironic :)

I did a 13 minute climb last year really hard and it estimated my ftp off of that. No way in hell would I be able to hold the number it said for an hour. Probably like 20 watts less and it would have to be on a climb too

Sounds similar to me - it estimates my FTP of a 11-12min REALLY hard climb. I did the climb at around 369watts, and was cooked after 11-12 mins. Strava estimates my FTP at 352 (!), which (unfortunatley!) grossly overstates my abilities. For comparison, WKO4 has my mFTP around 325 (based on a a couple years worth of powerfiles), and even that seems optimistic IMO, but FAR better than the strava-estimate.

I suspect the strava-guys are more attentive to pleasing our egos than giving an exact estimate...!

I have been confused by Strava's estimate for a while. Strava says my "Estimated FTP" has dropped to 229 from ~280 at the beginning of May. However, the power curve for the past six weeks shows the following: 8 minutes (321 watts), 10 min (293 watts), 20 min (268 watts), 1 hour (240 watts). Those values came from 3 different rides over the past 10 days. So, Strava's current "Estimated FTP" appears to be 95% of my 1 hour number ... I do not plan to renew my premium membership.

For me it's actually the other way around. I think Strava is underrating my FTP by 15W at the least. Haven't done alot of max efforts lately and no 20 min test or so, but enough stuff at theoretical FTP to know it's higher than what they estimate me to be at. But I can't blame it, it probably just looks at max power. Isn't this what most of us do when determining FTP from a test as well?

Edit: I just looked at the graph again, and it seems like it does more than just look at a 20min max, because for me the estimated FTP was at 96% of 20 min power at that time, which might suggest it scales it based on how it relates to other max efforts. i.e. if you have relatively poor shorter max efforts it might think you fatigue slower. Problem there is it assumes that just because you're not reaching these numbers (because you might not train like this) doesn't mean you're not capable of producing them. But this is a problem that I have with predictive things like this in general, not unique to Strava.

Any idea how or why it chose this format to calculate? I literally have no idea which ride it pulled my data from. As others have found its about 15 watts higher than my road bike test and 30 watts higher than my TT bike test. I like to analyze power from rides but have always found this aspect of premium puzzling and my membership is coming up.

I looked mine up after reading your first post.

My power graph and FTP is shown for 2 periods; the last 6 weeks, and all of 2016. The 2016 number is higher, and within 10 watts of the FTP I got from my last TrainerRoad 20 minute test. The last 6 weeks number is lower, but I've been doing a lot more longer sessions at lower power as I prepare for my next IM.

Maybe Coggan posted it while wearing this t shirt and stroking his handlebar mustache?

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Zen and the Art of Triathlon. Strava Workout Log
Interviews with Chris McCormack, Helle Frederikson, Angela Naeth, and many more.
http://www.zentriathlon.com

Apologize in advance for derailing this slightly from the OP's question.

That said, if I understand you correctly, the recommendation would be to avoid deriving FTP from a 20 min climbing segment contained in a longer (call it 3-4 hour) ride? Why or why not? Simply want to avoid the painful testing protocols where possible, but also want accurate numbers so if the testing needs to be done, well....

It is common to be able to produce more power climbing than in aero position on a flat section of rode. In this case, the FTP derived from a climb could mislead when developing target power for a triathlon.

My strava-guestimated FTP is equal to about 32 minutes on my current power-duration curve. AKA 94.3% of my 20 minute power. Frankly I think it's about 5-10 watts high

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What can I say, I like Alanis Morissette's take on the word.

Some lead, others follow.

For me it's definitely way to high. Strava's 'guestimate' currently says my FTP is at 355. I did a 10 mile TT about five weeks ago at 365 watts and just over 20 minutes. There is absolutely no way I could do 10 watts less for another 40 minutes. I'm closer to the 335-340 range currently.

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Your power is like mine. Strava had my ftp at 379 watts after I did the climb. For 13 minutes I did 401 watts. I could probably do 360 for the Whiteface climb, but not on flat ground on a road bike.