Would love to see an assortment of results for people between 20 minute test values vs. xert values.

today i went into xertonline for the first time
i synced last 2 years of Strava
I was training these days with my assumption of 260W FTP. It gave me 264W
I am impressed

I've been happily using Xert for the last two seasons. Have you read DCR's review of the main Xert site? His review does a great job of capturing the usefulness of the app, including the FTP (and fitness signature) calculation, and the nuances of why you might want to or not want to use it as a triathlete.

The What's my FTP app is a bare-bones version of Xert's full-featured fitness signature calculator. Based on my limited testing, it works really well for a quick-and-dirty field test, and is very close to what the full Xert site calculates.

The idea isn't that you would use it in a 20-minute test—it has its own protocol—which is basically "ride until you're exhausted." Quickest/easiest way to do it is with a 2-minute balls-out effort. As long as you're completely spent at the end of it, you've got a decent estimate. If you only pushed 90% of the way, then try again as soon as you want—it will pick up where you left off.

I've found this useful to do quick tests of position changes. I've been moving cleat positions, pad heights, seat heights, and have found Xert's fitness signature calculator invaluable. I've been using this app to hone in on exactly how much power I'm losing when in aero vs. climbing position vs. full road position.

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_____________________________________________________
George Dedopoulos | @geodee | geodee.com | Team Atomica | Toronto Triathlon Club

I get that the idea is that it'll give you an estimated FTP calculation base on daily rides/efforts. I'm curious what happens when a rider has that data page displayed during an FTP test (20-minute, 60-minute...whatever) and he now sees real-time where he's at. Extra motivation is right there.

I'm going to load it onto my 920 since I'm due for an FTP test as I hit an 8-week specialty phase for a 1/2 IM race. I have an accurate ftp number from a 40K race and will see how a 20-minute protocol with this available works out.

Did you use their workouts?

If so, how did you choose which ones to do. When I used them they had 3 or 4 workouts that were geared toward sprint time trialists and I got no suggestion for anything else to do.

Ah, I get what you're saying. If it all works as it's designed, during a 20 or 60 minute steady state test, the calculated FTP should slowly increase to your actual FTP by the time you hit the wall. It very well could be a good motivator! Totally worth trying out! I'd be curious to hear how it works for you.

If you find it doesn't seem accurate, or if there is a particular situation that breaks the algorithm, the developers are pretty responsive, and would love the feedback.

Last time I did a 20-minute test, I didn't realize how much fitness I lost. I went in way too hard, and ran out of steam by the 12-minute mark. So at that point I just gave it all I had left, knowing that with an exhaustion-level exertion it would have enough data to work with. I got a useable FTP to work with, even though my 20-minute test was technically failed.

Inversely, if you're feeling strong at the end of a standard 20-minute test, pushing harder for the last 5 minutes is... okay, but not really standard protocol, and kinda craptastic. But Xert will figure it out if you keep going or push through to the end.

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_____________________________________________________
George Dedopoulos | @geodee | geodee.com | Team Atomica | Toronto Triathlon Club

But more importantly, what does Dr. Andy Coggan think about this?

I use their workouts during the winter, but have been outdoors and semi-structured since the spring. I usually have an idea of what duration I want to target beforehand (usually 1x short Vo2 efforts, 1x sweet spot, and 1x long/cornucopia workout per week), and choose from there.

The workout suggestions I have mixed experience with. I don't totally understand how it works. It looks like it should base workouts around your A race, but I don't even know if it knows what kind of race it is.

So yes, there aren't a lot of different workouts if you specifically only want to target sprint TT durations, and if it keeps suggesting those, then I'm not sure how to interpret that. How long ago were you using it? The app is constantly being updated and having new features added, so this may have been changed.

There are a whole bunch of new workouts that behave differently than other time-based workouts. The smart workouts have variable interval durations, depending on how you're responding to the workout (and how well you're performing it). I found that the time-crunched sweet spot workouts were amazing for generating high amounts of training stress.

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_____________________________________________________
George Dedopoulos | @geodee | geodee.com | Team Atomica | Toronto Triathlon Club

I saw this on the DCR site as well and just doesn't make sense to me. I can do 542W for 2min but I am more a sprinter/pursuiter type (as confirmed by blood lactate test) and I am pretty sure that in my case a 2min test would vastly overstate my FTP.

Put another way, I know climber/TT types that I ride with that can't do near what I can do for 2min but have a much higher FTP than I do.

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Amateur recreational hobbyist cyclist
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099

I get what you're saying. If you were using a linear model (I.e. If your 20-min value is 105% of your 60 minute value, then maybe your 2-minute value is 200% of your 60-min), then you're right. That would be a horrible way to guesstimate FTP, and most likely completely wrong for most people.

The Xert model also takes into account your absolute Peak Power (1-second value), and your High Intensity Energy (W'). The HIE is basically expressing how deep your anaerorobic reserves are. So since you have a high HIE, the app should take that into account when it calculates your FTP and subtract the HIE from your 2-minute effort.

I totally get how it can work in the full app with your full history of workouts, but I'm actually surprised at how accurate the Garmin app is at pulling this info from such limited data.

It is one of those things where the more data it has, the more accurate it will be though.

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_____________________________________________________
George Dedopoulos | @geodee | geodee.com | Team Atomica | Toronto Triathlon Club

I'm in the same boat as you. It's a free app though, I might install it and try just to see what it gives me.

I used it last spring/summer until the free trial ran out.

I liked the way it classified the rides and told me where I was strongest and weakest, but at that time there was no (or I couldn't find) suggestions as to what I should be doing to help me progress. My questions went unanswered in the google group so I just deleted them (cuz I thought it was a taboo or something) and left the platform.

When the free trial ran out and I would have had to pay, I didn't want to pay for another training log.

If you're more of the fast-twitch type, before you do an exhaustive effort, do a maximal power (peak power) effort. This helps the algorithm estimate the high intensity energy/capacity contribution to your efforts.

The algorithm doesn't look at any average power numbers. It looks at how your power declines with fatigue to obtain your FTP.

Hope this helps.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Could you explain this a bit more (without giving away too many secrets)? Are you saying that the algorithm looks at how maximal efforts change over the course of the workout (i.e., what's the delta between my 2 min maximal power at 10 minutes into a workout vs 2 min maximal power 60 minutes into a workout)? Or is more similar to what WKO/Golden cheetah do where is compares 1 sec maximum power to 2 minute maximum power to 10 minute maximum power and then does some form of curve fit to identify what FTP is?

It never looks at 2 minute or X minute maximal power. It uses an algorithm that determines Maximal Power Available (MPA) second by second and reverse engineers your FTP from points when your power exceeds your presumed MPA based on the displayed FTP. Eventually it reaches an FTP where the MPA calculated is always above your power output.

Have a read through our blogs to get a better sense of what MPA is all about. It's a very powerful (excuse the pun) concept. :-)

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Can't tell if this was supposed to be pink or not.

Seriously thinking about trying this out...

It looks as if your implied question is being ignored here as well.

Just uploaded my last year of Strava stuff as well. Haven't done an FTP test in a while though... My last 20 min test in January 2016 and averaged 317W. I feel a bit stronger these days, recently put a 9 min "to failure" effort at 350W. Xert estimates my FTP at 334W. I don't know what to say... I find it a little too optimistic.

Hi Armando,

This thread got me to try out XERT - pretty cool. One question on the smart trainer workouts: does it have a function like Trainerroad does to use an external power meter to control the resistance on your smart trainer? I think I spied the ability to plug in an offset value, which is ok but not quite as desirable, since my Kickr's offset from my Quarq varies depending on how much wattage, temperature changes, etc.

Another question: does your system take climbing into account when performing its analysis? As I was importing rides from Strava, I noticed dramatic up and down movements in the estimated FTP, with the upswings driven by rides in hilly terrain and actual hill repeats and the downswings driven by trainer workouts. While I enjoy seeing higher numbers, I question their applicability to a flattish Ironman course.

Regardless, cool system you've come up with!

Ian

Thanks Ian!

Both Xert Mobile and the Xert CIQ Player perform Powermatch. In fact they maintain slope and offset between the two, updated in real-time .. cool? ;-)

At the moment, we only look at power data so unfortunately we don't recognize a difference between a climb and a trainer ride. You can of course analyse them for differences which is quite a useful exercise. We do have users that mix and assign different fitness signatures for different types of activities they perform. We have some ideas on how to better manage this that we are looking to implement in future releases.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

I'm biased as I ride with Armando, but I uploaded my Strava data into XERT and got a 318w FTP, when I've always used 315w through testing and educated guessing as my number. I'm a fan.

As i've mentioned to Armando, it will be sweet once running and swimming are factored in for predicted tiredness scores, but this is another fun tool to work with.

Ken

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"the trick is to keep losing weight until your friends and family ask you if you've been sick. then you know you're within 10 pounds. if they start whispering to each other, wondering if you've got cancer or aids, you're within 5. when they actually do an intervention, you're at race weight." - Slowman

From what I've read, every time you hit lap in the watch it will reset the FTP estimation value, correct?

Is there a way to disable that option? If I hit lap for each of my intervals, then FTP value would be resetting a lot, and that might impact the FTP estimation during a ride?

There are app settings that allow you to enable/disable reset on lap and to show FTP in W or W/kg. Using GE or GCM to configure these.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Hey Ken! Thanks.

This is one of the priority items on our roadmap.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

I installed this last week and out curiosity I've tried three ftp attempts. I'm impressed as they all came in within about 3 watts of each other and about where I that my ftp was. Plus I find the real time build and graphics quite motivating as I push myself as hard as possible. My last attempt yesterday I maxed my hr at 175 bpm which is two beats higher than I have ever seen on the bike. Best of all ... I'm not wasting 60 or 20 minutes trying to find a flat course to carry out a proper ftp protocol. I'm sold.

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Swim - ( x ) All good ( ) In the shop
Bike - ( x ) All good ( ) In the shop
Run - ( ) All good ( x ) In the shop

I loaded my data into Xert. It's over estimating my FTP by 10+%.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Hey Alex!

Four things:
1. If you're more of a fast-twitxh type, be sure to push out a peak power effort first If the value is over 1000W, it will make some minor adjustments to reduce the impact of high intensity efforts towards your FTP number.
2. Update the app. Latest version is best.
3. Be sure data quality is good. (goes without saying but you should look at the data afterwards).
4. Send us the file. At this moment, if you follow 1 and 2, overshooting by 10% is highy unlikely. We'd like to have a look at the data.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Hi Armando

I don't have a device compatible with the Garmin app. I loaded my data into Xert online. I know for sure the value it shows is over estimated.

I'll do a sprint effort when I get back to the track. Not overly fond of doing those on my road bikes while I'm overweight. Normally peak power is close to ~1200W.

Cheers
Alex

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Ah. Can we have a look to see what may have caused it? Sometimes simply *seeding* your progression can correct and improve overall results. There is an FAQ on that.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Color me impressed and great idea for the free app as it lured me on to the platform. I've used it now on three rides; twice on my road bike and once on my triathlon bike. My road bike FTP is about 18 watts higher than my tri bike. It nailed my numbers within a few watts on each bike. Very cool.

Thanks! that worked.

I tried that but might not be doing it right as it made no difference to anything. You may look at the data. .

Keep in mind I'm trying to start riding again after a very long time away from the bike (aside from the odd bit of riding here and there) and my last race season was 2011. First ride in Xert calendar is 18 May this year. You can assume CTL = 0.

My FTP W/kg is at least half of what it was then (power low, weight high). My local terrain is mostly rolling hills, some flat roads to choose, and accordingly to lug my fat arse over all the hills it's nearly a max effort so I don't fall off!

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http://www.cyclecoach.com
http://www.aerocoach.com.au

I seeded your progression for you. You'll notice that you only have 6 rides with breakthroughs (these are circles on your progression chart), according to the seed value I used. I think the results are decent and your ride on July 18th was exhaustive and expressed some good numbers. You can see that you're strengths are more geared towards shorter duration efforts.

Many of our users are seeing multiple breakthroughs in a given week, often with "near" breakthroughs, the term used for open circles that identify a slight drop in fitness. This is akin to doing an FTP test and seeing a 3 or 4W drop in FTP which could be due to a variety of reasons. Fitness often bounces back with a real breakthrough soon after that.

These breakthroughs act like a control system, keeping all your fitness numbers dialed in for each ride or workout you do. Xert does this automatically in the majority of cases but where fitness isn't expressed often or there are errors/offsets in power numbers, manual intervention may be required and there are tools to help with that.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Thanks. My ride on 18th was over part of a course I've chosen for a training camp I'm running at end of August. It was quite lumpy and challenging for a fat bugger like me.

With the revision Xert suggests my FTP is at a power I reckon I could sustain for perhaps 15-min. WKO4 suggests my FTP is 7-8% less than the Xert estimate. The WKO4 model estimate is closer to reality IMO. Do I have a long TT or MLSS data? No. Maybe I'll knock out some efforts in the weeks ahead, perhaps at the local velodrome.

Will see how it plays out over the coming weeks as I progress. It's no big deal, I've no competition goals, for now the goals are about life and getting some fitness back. I donated my TT bike to my club as i never expect to ride one again. If I ever race again it'll likely be local low grade stuff for fun.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Have a read through our glossary entry on Power Curve. It can offer an explanation of the discrepancy. Use of MMP data will almost always result in lower estimates than what Xert estimates.

We've recently added a new concept we call "Difficulty" which influences your ability to hold FTP for longer durations. In general, those with greater training load have an easier time handling efforts of greater difficulty. Longer FTP efforts, particularly if there is variation above and below FTP, are very difficult but become more bearable the more you train.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

It might be a lower estimate than Xert, but it's more realistic.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Excited/interested to see what it says during my ride tomorrow. Uploaded a years worth of data and it has me about 20 or so watts lower than what I am. Didn't look through everything but had Oly races at the number it estimated. Either way it's pretty cool. Maybe their is something up with the data I uploaded.

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Twitter - Instagram

Thanks for sharing. We had thought that it would be useful in this scenario and glad so to see it work for you! Using it for comparatives, particularly when it can be used to inform decisions, even race-day decisions, is an area we'd be very interested in hearing from athletes.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

I'm very impressed with the app. Is there a way to record each trial FTP in Garmin connect with data from that day's ride? It would obviously very handy to use the app weekly and build out a graph over the year.

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Swim - ( x ) All good ( ) In the shop
Bike - ( x ) All good ( ) In the shop
Run - ( ) All good ( x ) In the shop

I went to my local outdoor velodrome today and took the road and track bikes. I did a session on the road bike, just steady with some 2-minute efforts, a couple well in control, then one harder, then one at close to if not at max effort - had to wing the pacing. Must have had some impact as had a bit of bile coming up some minutes afterwards. The 2-min max was 327W (post amputation best is 446W).

Then I got onto the track bike and did a couple of short sprint efforts with a peak of 1210W, which is right in line with what I expect with no sprint training. Finished with a one lap all out effort, although I think my gear was a bit light as I peaked at 129rpm and I've not done any track work for ages. 611W for 27 seconds.

Xert updated my FTP to 208W, high intensity energy to 22.4kJ and peak power to 1210W.

Xert's FTP estimate is 106% of my current best 20-minute power but I've not done a 20-min test effort as yet.

The HI value is pretty generous as well.

Peak power value is same as power meter recorded as peak power.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

For kicks I tried the Xert Garmin Connect IQ app Saturday on the Edge 820, but I knew beforehand that I probably wasn't going to be able to fully utilize the app for its intended use because I was in a small leisure group ride. It was interesting to watch it spin up as the torque increased climbing up some short rollers. I would see a bit of a climb coming and think this is the one that will be long enough, but I always hit the crest of the hill and the intensity would drop off as we cruised down the other side. I think the highest I saw it get was 160.

Not that it matters because one can keep mental track of the highest number recorded, but I have my Edge set to lap at 20 miles so it clears or sets it back to the 100 start point. Just so happened that I was on a good climb and the suspense was building, but it cleared right at 20 miles. Just my luck :-)

I tried it again on Sunday, but never really got a clear stretch of road to really open up a sustained effort. I am recovering from torn PCL at the moment so I am not going to attempt higher intensity efforts just yet, but I hope to give it an honest try at some point in the future and see how it lines up with what I am using in WKO 4 and what it estimates as my mFTP.

Cool little app to try out.

BTW, you can turn off the "reset at each lap" feature so no need to watch your FTP reset to 100 in mid ride.

Your results are actually pretty cool. Is it ok with you if I use some of your charts to explain your results?

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Knock yourself out, although I'm more interested in whether my results are useful than whether they are cool.

While I have no specific personal goal other than to start riding regularly again and gain some health and fitness benefits, I realised a few years ago that psychologically I'm not much good at exercising but rather I am usually pretty good at training. So I'm looking at analytics with a coaching eye, rather than for my own personal needs. IOW I'm asking myself the question: is this something that provides actionable intelligence beyond what I already have, know and understand?

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Alex,

Here is your Progression Chart. Your Form is red because you're starting from 0 and don't have much data in the system yet. Xert found a few breakthrough activities and has very little to establish a good esimate of your fitness. I'll discuss out the ride on July 18th below.

There isn't a lot to learn about training and progression from your chart given the lack of data. There is some correlation between FTP (gold hashed line) and Training Load (black line - simlar to CTL).


Here is another progression chart where there is an intentional effort to push up threshold with lower intensity Training Load. Notice how there is little red (Form being too negative). In the end, the rebound created an FTP that significantly overshot the value expected from Training Load. Hire that coach.


This Progression Chart is quite different as there is a consistent demonstrated progression. Training load and FTP is highly correlated. Each breakthrough is a medal (gold, silver, bronze) and "near" breakthroughs (circles) are slight declines in FTP. Note that we're picking up these changes once or twice a week. For those new to Xert, imagine if you were to use "What's My FTP?" on every ride and you're riding hard group rides and races on a consistent basis. Xert's ability to track subtle improvements and declines in fitness is pretty remarkable.


On your July 18th ride, I zoomed in to your best 20 minute effort. What you'll note is that Xert establishes your FTP as 208W from this activity even though your AP for the 20 minutes is 189W. Using MMP from this ride will not provide any insight, unfortunately. Xert looks at Maximal Power Availalbe (MPA) as it rises and falls and uses it to estimate what your FTP is likely to be in order for you to have *expressed* this MPA. The 20 minute effort had a great amount of variability (our Equivalent Power which is similar to Normalized Average Power is 231W. Check out or blog on Paradigm Shift to see the difference between them).

It would be impossible for your FTP be below 200W in order to express this MPA. Now since your Training Load is so low (35 from above) you likely would not have enough fitness for a one-hour FTP test. Many athletes that aren't trained will give up with "reserve capacity" meaning MPA hasn't declined to reach power at the point of failure, i.e. it hurts too much. You'll know this has happened when the athlete gives in due to Difficulty Score being too high for their accumulated Training Load. A maximal effort - where MPA and power do not meet - is not reached. Many of our coaches are keying on Difficulty Scores as a important number to track and improve in the athlete.

Note, as is described in the glossary on Power Curve, this 20 MMP effort, starts in a fatigued state (MPA is below Peak Power), has periods where power goes below FTP (even periods of 0 power) and ends in failure above your 20 minute MMP (near 400W). If this 20 minute effort is used to establish FTP or influence an FTP regression, FTP is likely to be grossly underestimated.



Every coach using Xert would tell you to use 208W as your FTP, even with such little information to go on. It is likely the closest you'll get to a number that represents the threshold between short-term fatigue accumulation and recovery. In some ways though, your FTP isn't as important of a metric when it comes to using Xert. Xert uses a Fitness Signature (which includes a Threshold Power) and uses this to determine your fatigue quite precisely (as in the chart) and this precision is what is used in designing and prescribing workouts. Xert Smart Workouts avoid using %FTP in workout design for this reason.

Xert is quite a shift in thinking for those that are used to the older methods of analysis. Many coaches that are investing in understanding it, are able to provide their clients unique perspectives and interpretations of their fitness that have never been available before. Our self-coached athlete customers like the ability to get precise feedback on fitness improvements and the availability of highly personalized training that *knows what they can do*.

Good luck. Hope this clears up a few things. Time to get back to work!!!

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

I don't see the correlation you refer to. The lines often diverge and go in opposite directions, and sometimes the same direction.

If you are doing regular hard rides and/or races, then picking up on form changes should be pretty obvious.

How do you find and zoom in?

I would be ignoring NP or proxy equivalent values for just 20-minutes. It's just not long enough to be paying any attention to.

I find the statement that I don't have enough fitness to ride hard for about an hour to be absurd.

My fitness is what it is, and what I can maximally sustain for say around 40-60 minutes would be a genuine reflection of that.

If I am unable to repeatably do longer interval efforts at 208W, then there is no way that's my FTP. It matters not what my training load is, nor what Xert says or any model says. If I can't actually sustain the power for longer durations, then it's clearly not a maximal metabolic steady state.

Now it may well be that I can hold 208W but just don't know it.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Armando. Is there a way to save the ftp result to Garmin connect along with the ride stats? I like to track it and I see ftp is a parameter tracked in Garmin connect. Thanks

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Swim - ( x ) All good ( ) In the shop
Bike - ( x ) All good ( ) In the shop
Run - ( ) All good ( x ) In the shop

Did a Zwift race today with the Xert app up and running. A few things to note before going into what the result of the app gave:

1) Last calculated FTP was 4 months ago in a traditional 20-min test: 330W. I've done a TON of hard training since then, with many workouts that I would think pushed that number up.
2) I raced Racine 70.3 10 days ago and have recovered really, really well since, and haven't run or swam at all -- 100% bike riding in those 10 days, so I was pretty primed for a good effort today.

Result: FTP of 355W. Spent 12 minutes 8 seconds at 380W AP, 380W NP. Power file for ride: TrainingPeaks

I think the app may be a tad higher than what I could sustain for 20 minutes, but probably only by 5-10W. Pretty awesome to see that FTP estimation in real-time. At around 8 minutes in when it passed my 330W FTP I had a huge surge in motivation to push that number up as high as possible.

Unfortunately, not at the moment. Tracking is only available with http://www.xertonline.com.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

I would say that 355W would be very close to your FTP. If you obeyed the FTP to 20 minute power 95% rule with your 380W effort, your Power Curve would look like:

https://www.xertonline.com/calculator?power_0=380&duration_0=728&power_1=&duration_1=&power_2=&duration_2=&action=calculate


Which estimates your FTP @350W. However, note that your 12:08 effort had some periods below FTP which would imply that you could sustain a slightly higher power for that duration if you paced it more evenly. Hence, FTP @350W is probably a bit low.

Thanks for your comments.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

So the What's My FTP results are not saved anywhere?

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Janyne

I made the mistake of not checking the value just before I finished a hard ride and pushed the stop and save buttons a couple of days ago. Since I was running What's my FTP on the second screen which I hadn't had up I was disappointed not to be able to view the value after saving the ride. I suppose there's no work around for this?

Hugh

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Genetics load the gun, lifestyle pulls the trigger.

As mentioned, you can track via Xert Online. It is a subscription-based service (our families keep demanding to be fed) but there are a host of other capabilities like structured workouts and the Xert Progression Management Chart to go beyond just measuring and managing your FTP. Do check it out.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Just returning with an update.

This past week I've:
- tested Pmax with a couple of sprint efforts at the track
- tested 2-min power, also at the track
- today did a "fill the right" ride with 2-hours at hard tempo (what I call MIET - moderate intensity endurance training). It's taxing and requires concentration.

These were not done for the sake of MMP curves or other models but rather because they were part of a plan I have to get enough fitness to do (and at least enjoy) a challenge ride next weekend.

Today's ride did indeed fill out the right of the MMP curve although the left part of the curve curve is still a bit step like.

Based on 2 hours at an average of 188W today (NP 204W), then my FTP is likely in the 200-205W range. From my experience of racing, a hard 2-hour NP at FTP is about right for me.

Xert has me at 208W, and WKO4 at 203W. That's not too bad. I still think 208W is a little generous but I'm not going to quibble over 5W.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

If we look back to that breakthrough ride on July 18th, another way to explain the numbers is to use a signature of Peak Power=1229, High Intensity Energy=25, Threshold Power=203. If Xert had your Peak Power a bit higher, this would have been a more likely outcome of the extraction and we would some closer to your expectation. Xert will hone in on your numbers over time and look for small variations in the signature parameters. This breakthrough ride is an example. Since the ride has no MMP best efforts, it would not be part of any FTP regression using MMP. But with Xert, the ride stands out as if a spotlight was shone on it. It describes your fitness on that day. This is how Xert differs. The frequency and sensitivity to variations in fitness - not just to FTP but also to PP and HIE - allows unique, heightened visibility to how interventions are affecting the athlete's fitness. It is a powerful tool when in the hands of the coach or athlete that understands the principles.

Thanks for checking things out Alex and following up with your positive comments.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Thanks Armando.

My maximal 60-min NP for the ride told me it was a stand out already. It was 17W higher than for any previous ride in the current training "season". I've since come within a handful of NP watts of that day a couple of times which suggests it's not an outlier.

I think the Xert HIE is an overly generous estimate.

I'm still coming back to my fundamental question of what actionable intelligence am I getting from Xert that i don't already know? i.e. something useful that I don't already know or suggest doing something that I wouldn't already.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Actionable intelligence depends on the practitioner. There are many, for example, that would argue that power data provides no actionable intelligence over heart-rate data. Someone that knows how to use a slide rule would say that a calculator provides no actionable intelligence. I think one would have to take into account the practitioner. Many feel quite comfortable and adept at using older methods and are skeptical of our newer methods. That's normal. But there are growing number of curious and adaptable folks out there that have found new ideas and approaches that they may have found to be more opaque or difficult to interpret using the older methods. Not everyone will get it right away though as the concepts are still new. In due time...

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

Hi Armando, I've read articles on its use so far and nothing stands out for me, which is why I ask.

I think you know my ability to analyse and that I have a deep knowledge of and an understanding and delivery of the practical application of power meter data. I've been around the block a few times with this stuff. I don't however ever think I know it all or there is nothing new to learn. That would be a folly.

So on the basis of someone not starting from scratch, I'm looking for advice on what practical actionable intel it provides that is also novel, or what it does that would make my coaching business operate better.

I ask because I'm not at this stage seeing it, so help me see. If it's essentially just telling me what i already know via my long experience and existing tools of the trade, or its not really going to make my life as a coach any easier, that's OK. It's then an option for those newer to power but nothing more or less than the other analytics options available.

In essence why should I spend my money to use it?

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http://www.cyclecoach.com
http://www.aerocoach.com.au

Humility is a good thing to hold, but as far as those who share training information on the internet you and Ric know more than most and are rarely stumped on a question or issue. Just thought I would chime in and say thanks as I started learning how to train with a power meter years ago (about 2006) on a different forum and have always appreciated your contributions. Sadly I still don't know much in terms of training with power so please don't stop dropping nuggets of tips now and then. :-)

Thanks! I always hope to learn more and happy to share.

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http://www.cyclecoach.com
http://www.aerocoach.com.au

What is Xert's definition if FTP?

From http://baronbiosys.com/...e-ftp-determination/


"Although FTP is often characterized as the power you can hold for 1 hour, other methods such as the 20 minute test have been used as ways to approximate this number using the 95% rule. Our app works differently in that it looks for the power that you should be able to sustain for a very long time. This is often very close to your 1-hour power, perhaps a few watts above or below and for all intents and purposes can be used in place of FTP. Some say that this represents a better threshold power, and is what Xert uses."

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

http://wp.me/p7MgIM-gh - Here's a review and a video, and also several stills, of the app in action. I'm pretty convinced - it's probably 98% accurate.

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Richard Wharton, USAC L1 since 1997.
Technology, Application, Attention, Success
http://www.onlinebikecoach.com, http://www.cyclingcenterdallas.com
#whareagle, #leavewithnothingleft, #knowyournumbers, #numbersdontlie

To clarify a bit, FTP is colloquially regarded as the average power you could sustain for an hour. 40k TT average power has also been described as a way to estimate FTP which could mean it is more or less than an hour. There have been many debates as to the meaning and/or definition of FTP and I don't want to revive these arguments. Suffice it to say, the results you get from the app are a reasonable estimate of the value you should be using as FTP in your training. Most athletes (with very rare exceptions) have reported that it provides a value that is very similar to what they believe their FTP to be.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

I've been using both WKO4, Golden Cheetah, Xert and the Xert app for a while now.

My clear experience is that mFTP in WKO4 and all of the CP models (though to different degrees) in Golden Cheetah are far more prone to erroneous estimations due to training variations than either of the Xert methods.

That is to say, WKO4 and Golden Cheetah have changed their estimations of my FTP/CP drastically, as my training has gone from being focused on longer high intensity efforts during the winter racing on Zwift and to mostly riding high intensity chasing local hill climb records for short durations during the summer.

At one point during winter, WKO4 had me at an mFTP of 279, while the two parameter model in Golden Cheetah had me at a CP of 277.

Now, for the last 90 days of training, WKO4 gives me an mFTP of 235, while the two parameter model in Golden Cheetah have me at a CP of 231.

Meanwhile, the Xert web tool had me at about 260-270 FTP during winter and is presently estimating an FTP of 280.

This progression in the estimation by Xert makes much more sense to me, as I am indeed stronger now than in the winter (based on wattage at shorter durations, feel and hill climb times), which is completely contrary to the FTP/CP estimations of WKO4 and Golden Cheetah.

It's worth noting that WKO4 and Golden Cheetah have changed their estimations of my FRC and W' to reflect my change in training and riding style, but this has happened at the expense of the accuracy of their estimations of FTP/CP.

As a further point of reference, the Xert Garmin app estimated an FTP of 267 a few of days ago after some hard, short efforts, where my form/TSB in either training tool was around 0-5, which means I could have been fresher/stronger.

It seems to me that the Xert web tool strives to predict and estimate your FTP for an optimal and fresh training state (what your FTP would be if you tapered properly for a race or FTP test, for example) regardless of how you're currently training and riding, while WKO4/Golden Cheetah to a much larger degree simply mimics your training regimen in their estimations and therefore change the modeled FTP wildly in accordance with changes in training.

My impression is that the Xert Garmin app is a happy medium between the prediction of an optimal state FTP (osFTP) of the Xert web tool and the reflection of your current training state FTP (tsFTP) of WKO4/Golden Cheetah.

In other words, the FTP estimation of the Xert Garmin app appears to reflect your current training state more closely than the Xert web tool, but it does not require you to perform efforts at threshold intensity for longer durations to achieve this, as WKO4 and Golden Cheetah do.

You might say that it's all a matter of the quality of the data the tools are fed, but why should I go to the trouble of spoon feeding my tools the specific data that they prefer, when I can simply ride as I please and still get accurate estimations of my FTP? (Not to mention my osFTP and tsFTP!)

WKO4 and Golden Cheetah honestly seem antiquated in this regard, though I continue to use both on a near daily basis for the many other benefits they provide.

To polemically expand a bit on how varying your training affects FTP model estimates, I would say that the closer your training mimics an actual FTP test of longer duration efforts at threshold, the more accurate the WKO4 and Golden Cheetah models generally become.

But this dependency on mimicry simultaneously renders the models irrelevant or inaccurate to different degrees depending on exactly how closely your training is tethered to actual FTP testing and longer duration threshold efforts.

In other words, if your training is far removed from threshold efforts and FTP testing like my summer riding is, the WKO4/Golden Cheetah model estimates tend towards the inaccurate.

If, on the other hand, your training consists of longer threshold efforts that approximate FTP testing like my winter riding did, then the WKO4/Golden Cheetah model estimates tend towards the irrelevant.

In either case, the model estimates are more or less useless.

The Xert models appear to avoid at least one half of the uselessness trap of this training variation of the accuracy paradox by not being tethered to mimicry of longer duration threshold efforts to a similar degree as the WKO4 and Golden Cheetah models.

Question is what do you feel the estimate is right compared to?

If you did a maximal 60min effort, what would think your power would be?

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Hamish Ferguson: Cycling Coach

As 60 minute power isn't FTP and Dr Andrew Coggan PhD wants to personally shoot the next person who claims FTP is 60 minute power, why do you think power over 60 minutes is relevant?

Training and Racing with a Power Meter
21 July ·
Can I just shoot the next person who mistakenly claims that FTP = 60.000.... min power?

In the winter, the threshold estimate of Xert was compared to the FTP/CP models of WKO4 and Golden Cheetah as well as high intensity threshold efforts that were in effect maximal TT efforts between about 30 minutes to 1,5 hours in duration.

In the winter, all of the estimates from the different tools were largely in accordance with each other as well as the actual TT threshold efforts.

As I've changed my training to not include any threshold efforts of longer duration, instead focusing on HIIT with shorter efforts between about 30 seconds and 5 minutes, both WKO4 and Golden Cheetah are now reporting an FTP that's about 40-50 watts lower than in the winter, while my monthly TSS has increased and CTL has gradually moved upwards from a low point of 50 in the winter to a high point of 85 in the summer.

As noted, Xert now estimates that my FTP is 280 which is a little higher than its highest estimate in the winter and almost exactly the same as the highest estimates of WKO4 and Golden Cheetah in the winter.

I could do a longer threshold effort to see where I actually end up at present (about 260-280 depending on freshness and training state, would be my guess), but I suspect that it's highly unlikely that I've lost up to 50 watts at FTP while improving other parameters of fitness as well as wattages at 30 seconds to 5 minutes, as WKO4 and Golden Cheetah would have me believe.

Of course, much of the reported loss is to do with the 90 day window that I've chosen to use in WKO4 and Golden Cheetah, as their estimates shoot right back up to about 260-270, if I choose to use data from all of 2017.

But if I do that, I lose the responsiveness of the model estimate, which you correctly value.

The more likely possibility than both an actual drop in FTP as well as errors in data is that WKO4 and Golden Cheetah can't accurately estimate threshold, if your training regimen does not contain efforts of longer duration near threshold.

It's the model accuracy paradox of training that I outlined in my previous reply: If you already have the wattage data from the longer threshold efforts, the model estimates are more or less accurate but also more or less irrelevant, as you already have the data; while if you have no data from longer threshold efforts, the model estimates could be very relevant, but in this case they're sadly more or less inaccurate, as the models appear to require longer duration threshold efforts to achieve accuracy. This is of course a schematic simplification, but it get's to the root of the problem with the WKO4 and Golden Cheetah models.

I'm guessing the WKO4 model reflects the totality of the specific training and efforts done by the riders used as its statistical foundation, and I would guess as well that all or most of these riders regularly did longer duration threshold efforts, which means that this type of training is what the model is primarily tuned for.

In other words, the WKO4 and Golden Cheetah models can't accurately estimate FTP based only on data from HIIT training at shorter durations.

Xert appears to have no such problem and its threshold estimate is therefore actually useable for me, as well as in line with my winter performance.

If Xert does turn out to also be inaccurate in its estimates based on my HIIT training, it seems reasonable that it's at least much more accurate than the estimates of WKO4 and Golden Cheetah, when they only have my HIIT training to go on.

I also suspect that my circumstances are far from unique, as many others vary their training or tend to avoid FTP testing or longer threshold efforts for whatever reason. I'm no coach (and as an aside, I've actually just cancelled my Xert subscription), but Xert seems great for easily getting an FTP estimate from riders you're coaching who are not regularly doing longer duration threshold efforts for whatever reason, and for whom the estimates of WKO4 and Golden Cheetah are therefore possibly inaccurate.

If the training state FTP or tsFTP from the Xert Garmin app could be incorporated into the Xert web tool to supplement its optimal state FTP or osFTP, that would be ideal, as the tsFTP seems to me to correspond more closely to the estimates of Golden Cheetah and WKO4 than does the osFTP of the web tool, while both Xert models are useable for shorter duration HIIT training, which WKO4 and Golden Cheetah are not (with regards to the model estimates, at least).

It's worth noting that the tsFTP of the Xert Garmin app is also the most responsive threshold estimate of all, as it reflects your FTP on any specific day that you use it, just as an actual FTP test consisting of a longer threshold effort would, without actually requiring you to ride longer duration threshold efforts.

None of the other models come close to this level of responsiveness and ability to reflect your actual daily training state FTP, while simply doing maximal efforts at any duration.

In short, the Xert models appear to have very minor practical constraints compared to the other models, and this has several practical benefits, as it means that Xert is compatible with and accurate for both a wider range of consistent approaches to training as well as larger variations between training types throughout the year.

What are you waffling on about Troll? I just asked what he thought his 60min power was.

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Hamish Ferguson: Cycling Coach

I'm pointing out that FTP isn't 60 minute power. It isn't my fault you forgot what FTP is this week.

But 60 minute power can be a suitable proxy, so Hamish' question is relevant and meaningful. He did not claim FTP to simply be equal to 60 minute power. :)

Again Troll, what are you waffling on about. I asked him what his 60min power was.

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Hamish Ferguson: Cycling Coach

Not if you can only maintain FTP for 30 to 40 minutes, in which case FTP would be underestimated.

So this continues;)

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Genetics load the gun, lifestyle pulls the trigger.

Hilarious

Seems like many assumptions being made. Many take a percentage of a short effort or ramp test as an indication of FTP. 75% of 3min power or the Max Min Power test.

This is where the Fatigue Resistance metrics in WKO4 become quite handy. A high mFTP and 30-40min Time To Exhaustion can tell a story.

We have that here in Christchurch with short steep hills and riders who do maximal efforts up them but don't go as hard on the flat for longer durations. One chap rode a 25km TT at a lower power than his mFTP. Another chap did a 20min effort and a 40min effort and saw his mFTP increase with a TTE of 60min. For racing a Normalised Power target for the first chap would be much lower than the second chap.

Biggest thing I see with these short tests or estimates based off such short is a overestimation of FTP. Easy to spot in WKO4 if you look at the fatigue resistance metrics.

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Hamish Ferguson: Cycling Coach

Yes, a high mFTP and Time To Exhaustion of 30 to 40 min can tell a story, that FTP defined as quasi steady state power for approx 60 minutes is utter garbage, yet for over a decade idiots thought that is what FTP was.

So what was the original definition of FTP? Obviously it was balderdash and things have moved on, yet people are selling apps which assume FTP is the power one can maintain for approx 60 minutes in a quasi semi state. But then, new FTP has moved on and FTP is the power one can maintain for anything from 30 to 70 minutes.

As New FTP is the equivalent of MLSS, people should go and get a proper power / blood lactate test and establish hard facts, instead of relying on snake oil.

More hilarity. And your confidence in lactate testing is based on what?

But seeing you are neither a coach or a sport scientists what is any of your sad ramblings based on?

Does internet trolling pay well!

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Hamish Ferguson: Cycling Coach

 I suggest you ask those that link FTP to MLSS why they have confidence in blood lactate testing, see below.

"As noted, MLSS is an exercise intensity that can typically be sustained for 30 to 70 minutes. Since FTP is a simplified tracking metric of MLSS, it has the same sustainable time range (not specifically one hour, as often stated by others). Since this roughly corresponds to the duration required to complete a 40km time trial, the latter provides an excellent estimate of power at MLSS, especially when you consider how flat the power-duration relationship is in this region. In addition to improved metabolic fitness being reflected in a higher power at MLSS/FTP, however, training also tends to improve the duration that exercise at this intensity can be maintained."

https://www.trainingpeaks.com/...tion-metric-in-wko4/

No, I asked for your thoughts. Do you have any of your own? Then I suppose when you are just troll, not a coach or sport scientist then all you can do is parrot others.

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Hamish Ferguson: Cycling Coach

I'd like to try and bring this issue to rest, once and for all, if I may.

For the moment, forget the idea that FTP represents some power that can be sustained for some duration. Instead, think of FTP as the power that represents some level that, above which, the work rate cannot be sustained without having the athlete accumulate fatigue and eventually reach exhaustion and below which the athlete is able to recover from fatigue. In Xert, this is simply Threshold Power (TP).

In Xert, we also introduce another parameter that detemine how much capacity you have above TP. This is called High Intensity Energy (HIE). And we also add in your highest power possible - Peak Power (PP). With these three parameters, called a "Fitness Signature", Xert models your fatigue as it increases with efforts above TP and decreases with efforts below TP, ultimately defining how much power you have available at any given moment - Maximal Power Available (MPA).

An athlete's Fitness Signature remains remarkably stable from ride to ride. This is great since the changes in Fitness Sigature variables are small, when efforts to exhaustion are performed, and we can readily see how your fitness signature parameters move up and down with trainig load. We can spot progress as the changes are in very many cases tied to the amount and type of training an athlete has been doing. Your Fitness Signature therefore becomes a set of variables that can be used to *define* your fitness level.

So how do we tie TP to other values that appear to be analogues, namely FTP or CP? We've seen the debates that have raged over how FTP and CP compare. If you use the Xert Fitness Signature calculator (https://www.xertonline.com/calculator), it takes 3 maximal, constant work rate efforts and determines the Fitness Signature and from the Fitness Signature, will plot out a power duration curve. This process is *not* a regression but a *solution* to the three points provided.

What you'll notice however, is that if you replace a data point with a very high power - 2000W for 1 second - the model mimics the 2-parameter CP model. But as soon as you reduce the 2000W to something more realistic, TP drops below the same value calculated for CP. So where there have been assessments as to how long CP can be sustained, TP would exceed that duration *whatever that duration may be*.

So how long can one sustain TP? To answer that question, we also have to ackowledge a couple of other phenomenons that we see in the data. Firstly, the prevalence of 1-hour efforts that end where our model-derived MPA and power meet at some value near TP is *extremely rare* in regular ride data. One might argue that our MPA isn't modeled correctly but the most likely reason is that athletes are simply unwilling to spend 1-hour at slightly above TP such that MPA drops over the course of the hour. In Xert, we introduced the concept of Difficulty Score as a way to quantify how hard an effort is to complete and a 1 hour effort slightly above TP has a very high Difficulty Score, suggesting that most atheltes would give up well before. Note that *giving up* means that they still had the capacity to continue but chose to stop or to reduce power below TP to avoid the discomfort. We also see that handling this discomfort improves with training, i.e. as traiing load increases, so does the athlete's capacity to handle greater difficulty increase.

The second factor is that TP and HIE (PP not so much) are affected over longer durations. We see them declining in order to determine MPA. With a declining TP over a 1-hour effort, this has the effect of reducing MPA for constant work rate efforts that we don't currently model in Xert. This is something we plan to add to the software.

In conclusion, if one simply looks at historical power data, it would be extremely rare to see a 1-hour effort that would have an average power near our model-derived TP. If this is how you choose to define FTP, then yes, TP overestimates FTP every time. In Xert, we use our fatigue-based model to look for a power level that is sustainable and determine this value using a consistent and repeatable method. We believe this is similar to how many athletes and coaches use FTP in training and thus see our TP and FTP as being the same in this respect. This value *could* be sustainable by the athlete for roughly an hour but the likelihood of this happening is limited by the athlete's willingness to endure the discomfort. Many think that they couldn't sustain our derived FTP for an hour when what they really mean is that they *wouldn't want to*.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts

I see it as two types of performance analysis. One pushes athlete to perform lots of short intense efforts to chase a higher threshold number that does not relate to actual long term endurance performance. The other pushes on to develop a base of fitness, a threshold number that relates to endurance performance, and the fatigue resistance to perform in endurance events. I know where I am putting my money and directing the cyclists who work with me in endurance events from 10s to three weeks!

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Hamish Ferguson: Cycling Coach

Just thought I'd revive this thread and give some kudos to Baron Biosystems on their app's accuracy. I have been using it pretty consistently to test my FTP with efforts around 5-7 minutes in length, and today I did a formal 20 minute FTP test to verify the app's accuracy (or my results from the shorter efforts).

I have done probably 5-6 "FTP Tests" with the app, chasing KOMs on Zwift on Box Hill (London) and the Volcano Climb (Watopia). Those efforts are anywhere from 5:50 to 6:30 and my wattage ranged from 420W to 433W on the climbs.

My most recent test on the platform was last week, climbing the Volcano in 6:29 at 433W (TrainingPeaks File: Volcano Climb), which the app estimated an FTP of 365W.

For my formal test today on Zwift, I held 381W for 20 minutes, resulting in an FTP of 362W (TrainingPeaks File: FTP Test).

The app was 3W higher than my classically tested FTP by 0.83%. Beyond accurate in my opinion. I'd opt for a 6:30 sufferfest over a 20 min TT any day.

All power is driven off my Tacx Neo, though I also ran my Powertap P1s alongside the Neo for the formal test, and they were lower by a whopping 2W (0.67% difference).

Thanks TriowaCPA. Feels like a knife to the heart everytime I read about someone doing an FTP test. Thanks for helping spread the word. Note that the latest iteration of Xert's algorithm incorporates some of the things we've learned from the What's My FTP? implementation. Users should see better analysis. So even if you don't have a Garmin device, using our web app will also provide you similar values for your FTP. Cheers.

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Armando Mastracci, Founder of Xert, an advanced data analytics and training platform. Blog, Podcasts