Is There Such A Power Formula?

CleeRider

If I can complete a 1 hour max effort (TT) at 200W - essentially my FTP. Is there a formula out there to use this info to come up with the number of watts to target when riding for 2, 3 or 6 hours such that those rides are also my best possible effort?

jgsi

That's not a good use of a power meter. ..you have in mind there.

sungod

it really depends on your training and stamina, if you train for power over longer durations you'll do better than if you only train for, say, one hour performance

you can try one of the online critical power curve models, but if you've no data on longer duration rides the results aren't likely to be that useful

http://www.cyclingpowerlab.com/MonodCriticalPower.aspx

neeb

CleeRider wrote:

If I can complete a 1 hour max effort (TT) at 200W - essentially my FTP. Is there a formula out there to use this info to come up with the number of watts to target when riding for 2, 3 or 6 hours such that those rides are also my best possible effort?

Basically, no. It would depend on your particular metabolism and also how well-trained you were over those durations.

Just as you can't predict your FTP from a 1 minute effort or a 5 minute effort (because these efforts predominately use different metabolic systems and different people naturally are better in some areas than in others), you can't really predict your maximum 3 hour effort from your 1 hour effort because the main factor that relates these is how you fatigue, and that's another thing that varies between different people as well as with training.

CleeRider

Thanks guys. It all makes sense.

neeb

I've actually been very aware of this non-constant relationship recently, as due to trips away and other commitments I've only managed to get out on the bike about once a week for the past 4 weeks or so. I can still blast off from home and keep up my normal wattage for the first hour or so, but my ability to sustain it has noticeably suffered and my power plummets in the second part of the ride.

cycleclinic

of course this is not how you are meant to use your power meter. You use it to target a power (using the 30 sec avg reading) for intervals and to track your weekly progression and stress/fatigue levels.

If you have enough data in golden cheetah for example you get a good idea of your fatigue rate.

In fact if power is plotted against 1/time (secs^-1) the plot should be a straight line.

So there is a formula but you need a good data set to see it.