Estimates of maximal power for long durations based on FTP?
 

(A short note first: I'm not a triathlete and since I hate cold water and my only swimming style is head-above-the-water breaststroke, I don't plan on becoming one either, except perhaps as part of a relay team. So this is not about becoming a good, or better, triathlete!)

Regular road racing time trials are usually limited to about one hour of riding (rarely even that long around here, usually 10-30 km rather than 40 km), and the most common definition of functional threshold power (FTP) is the power you can average for one hour.
The bike part of triathlon events where drafting is not allowed is essentially the same as an individual time trial, but (at least for HIM and IM, and longer events) for much longer durations than the typical one hour of road time trials.

My question is how close to your one-hour power (FTP) you would typically expect to be able to stay for the bike leg of an IM, or about five hours (give or take an hour).
Obviously, trying to estimate it from group rides of similar duration is very difficult, since they're much more variable in terms of power output. One minute you're in front, taking the full force of the wind and pushing hard, and the next you're at the back, loafing, shielded by a dozen riders in front of you. During a time trial, you generally keep power much more constant, and that allows you to ride with a higher average power.

I realize that there is no single answer, since genetics and specific training play a huge part, but a rough estimate should hopefully be possible. There are ways to extrapolate from sub-hour efforts to much shorter efforts with reasonable accuracy, so it ought to be possible to do the same in the opposite direction.

So, if you're an average guy (in terms of specific training and genetics) and your one-hour power is 300 W (mine isn't!), would a five-hour power be around 200 W? 225 W? 250 W? What would you suggest?

This assumes, of course, proper hydration, energy intake and position on the bike.

Eh, that analogy doesn't work because you have to swim before and run after. Really, the real race is the run. Train more, dork out less.

+1 Tri races are won/lost during the run. I see little variation in the bike speeds posted by the top contenders, and, similarly, swim times are comparable. Having the gas in the tank to turn in a winning pace on the run is what separates the pack. You question is much better put to criterium racers.

Disagree. In a crit power values are great to download after to review your race but near irrelevant in a crit. Doesn't matter what your FTP is; if you can't go with an attack or even just hold the wheel in front your race is over...

The triathlon bike leg is where monitoring power output based on FTP to manage effort to save enough for the run is where the power meter is golden. So easy to be caught up in the racing (for IM - all the months training built up into this day, getting out of the water with others around) and go out too hard whilst you are still fresh and pay for it on the run or a few hours later still on the bike. Though one of the tricks to a fast bike is also to swim fast and get in one of the fast bunches holding around the percentage FTP you plan on racing as even riding legally there is a drafting effect...


CdCf - check out the second edition of the Power bible 'Training and Racing with a Power Meter' by Hunter Allen and Andrew Coggan. This edition has a chapter specifically on training and racing Triathlons with a PM. There the have a table covering your question as I understand it. For an IM, guideline suggests to ride an Intensity Factor 0.70-0.76, 68-78% of FTP. So for your 300 Watt FTP example that would be 204-234 Average Watts. :thumb:

Obsessing about power meter numbers is a waste of time. Train more, dork out less. Unless you are in contention for the win for most of your races it's pretty pointless.

Sorry, I'd rather train and race smart, not train more. Especially as I get older, it’s all now about quality not quantity...

Most triathletes do not have the time or energy to just go out and churn out the miles. Even my biggest weeks leading up to IM consisted of only just over 420km on the bike, once you add the swim and run training the hours racked up to over 20 hours per week. And these were when I was younger. I can't expect my body to handle that volume as it once did!

More structured training within training zones to provide the greatest adaption and bang for your buck. Once you have ridden with a power meter, you quickly learn that most people including myself were going too easy on the hard sessions and too hard on the easy sessions. The result of this is that you waste time and valuable energy training in the wrong training zones and not improving.

I’m happy for you to just plod along and grind out mile after mile if that’s your thing, but there are others who use these tools and get great benefit from them. Definitely not a waste of time to those that are using a powermeter…

You could buy a cheap HRM and do the exact same thing too. If you think there is an exact power output you should be riding at, well, good luck with that. I don't know why trigeeks are so obsessed with geeking out with gadgets.

No, a HRM does not do the exact same thing. A HRM has been shown to not be an accurate measure of exertion as it is too easily influenced by many external factors. Diet, sleep to name a few... These are well know facts about the HRMs limitations.

I did use a HRM for a while and learned this very early on. It is useful to a point especially on the run during longer races as a way of making sure I wasn't going to hard eg. at the start of an IM marathon. But I stopped wearing it in sprint events as it would ramp quickly then continue without change. And now I use the PM on the bike, I don't even wear the HR strap even though the PM head unit stores the output.

Now with the PM I can accurately guage effort whilst training and racing. By the way the last three years since having the PM has been when I have only been racing on the road and velodrome and not triathlons due to running injuries. So I am a roadiegeek thank you very much. :rolleyes:

My preferred event is the TT and have seen the benefits of embacing sports science from using the PM to also the free speed by improving aerodynamics from a session in a wind tunnel back in 2008. You may ignore the science, but I gained an estimated 43 Watts saving at 40 km/hr!

You may start to realize more and more cyclists (road, tri, track, MTB and even BMX) are opening their eyes to the benefits of the PM. There are many available journal articles and studies which support Wattage as the current best method to measure effort on the bike. Feel free to ignore the decades of sport science that has gone into the ability to know the various levels according to Functional Threshold Power (FTP).

It's your choice to rely on old training philosophies and training methods, mine is to embrace what is the latest training knowledge and methods to improve.

That was slightly lower than I had thought. Well, my own guess would've been around 75 %, so I suppose it's at the high end of the range.

I'll probably get that book at some point, but I have a feeling it's aimed mostly towards racing, and training for racing. I'm only interested in long, steady efforts like TT and tri when it comes to power measuring. Actually, what I'm really interested in is the aerodynamics, and without access to a wind tunnel, the only shortcut to getting that information is through solo efforts with a power meter.

2nd edition of the book does offer more information about tri/ steady TT efforts. Percentages above are for triathlons - with average power low enough to factor in that the athlete has enough glycogen to complete the run.

If you are interested in the aerodynamics and haven't done so already - look at version 2 of the freeware software Golden Cheetah. They have created 'Aerolab' which has programmed Chung's VE model to calculate CdA from field testing.

If you have a power meter and you don't have the book, it's no wonder you're on here asking questions like this :) You need the book. It has all the answers you need. It's dirt cheap compared to the price of the power meter. I don't race at all and I don't feel like it matters one bit when reading the book.

Uh, ok. So if for some reason somebody might win some random race that really, nobody cares about, then power meter numbers magically matter? Give me a break.

You can use a HRM to keep yourself from running/biking too hard to or too easy. Percieved exertion is shown to match heart rate pretty well, so you don't really even need a HRM.


You can geek out all you want about power on the bike, but at any level of competition the bike leg WILL NOT WIN A RACE. That's been proven over and over. Training smart is a good idea, but obsessing about power numbers when your an amature racer is silly. If you can consititantly win races, sure, geek out to your hearts content.

I still don’t agree that RPE or a HRM is the best option. You are correct that the bike leg is rarely where the race is won, but is often where the race is lost. So riding to a power range calculated prior through testing and learning to [geek] ride efficiently (reviewing training file on the WKO Quadrant analysis chart) [/geek] means you will save more cookies for the run.

PM's are just another tool to add to the arsenal. Especially now when the cost has gone down to where they are much cheaper than many wheels or bike options, why be so negative when it is adopted by racers? As well as allowing riders to train and race smarter, they can be used to field test CdA. So for those without a local wind tunnel or wanting to spend the money to get tested (though worth ever cent IMO), the PM can be used to find the optimal position factoring aerodynamics and comfort which also has a huge impact on how the athlete can run off the bike.

How about the use of other tools then; such as wheels, aero frames or aero helmets? Where do you draw the line? Only allowed to be used by those winning? How about those who want to improve so they can win? How about those who just enjoy training any racing without any plans on being near the front? Why should there be restrictions if people want to use these or other tools?

I’m still perplexed by the trigeek comment too. This would be one of the first if not the first discussion directly relating to power meters in the triathlon section. Have you checked out the road racing section of this forum?

I'd like to point out that this makes no sense. If this is where it was lost, then it also means where it was won for somebody else.

Anyway, a minute is a minute. In the end, thats what it all comes down to. People have won ironman competitions partially based on being extremely strong cyclists, I believe 2004 was a good example of that.