"The 33"-Road Bike Racing - Setting FTP from ride data

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View Full Version : Setting FTP from ride data


ericm979
12-08-07, 04:38 PM
Today's group ride seems like it'd be good for checking my FTP- one hard > 20 min climb and a fair amount of extra-hard riding on the flat/rollers to stick with more powerful riders.

But using different methods, I come up with different numbers. If I use the Allen/Coggan method of looking for a 'step-down' in the power distribution graph, I see the largest from the 260-270 to the 270-280 buckets, suggesting an FTP of 270. If I take the avg power number from the best 20 min of the climb (263w, 4.1 w/kg) and subtract 5%, I get 250. Now I know I didn't go at 100% on the climb, I was saving just a little, but I don't think it was that much. I have a hard time setting my FTP to higher than my max 20 min power for the ride- that doesn't seem to make sense. What would you do?


cslone
12-08-07, 04:50 PM
How long was the ride? You can look at NP and at least see where it falls in comparison until you can do a proper test.

'nother
12-08-07, 04:51 PM
What would you do?

I think I'd keep those numbers in mind as a rough target when attempting a more controlled test (such as the one in the Coggan/Allen book), but not necessarily say that either one is for sure your FTP.

From my read of the book, I got the idea that it's pretty important to be able to repeat at least most of the conditions (route, warm-up time & intensity, etc.), to keep too many variables from changing when you re-test. My guess is, it would be hard to replicate the major factors of today's group ride in another 4-6 weeks when you want to see what effect your training has had on your FTP.


asgelle
12-08-07, 05:10 PM
http://lists.topica.com/lists/wattage/read/message.html?mid=910289158

waterrockets
12-08-07, 06:14 PM
I think I'd keep those numbers in mind as a rough target when attempting a more controlled test (such as the one in the Coggan/Allen book), but not necessarily say that either one is for sure your FTP.

+1 use the 250-270 for pacing a real test. If you're doing a 20 minute test, maybe start at 260W and see how you're feeling after 10 minutes.

Take a look at doing a Monod protocol test. I completed mine today with a 20 minute ride (see the end of the "training status" thread). I ended up with 1 minute, 5 minute, and 20 minute numbers. I used just the 1 and 5 to give me a target for this ride, and it ended up being exactly what I could do -- not a Watt higher. Monod is pretty cool.

Be careful testing on a 20 minute climb though. You'll end up overestimating your FTP because the climbing position is more efficient. You can't ride like that on the flats. I did a rolling course today and spent time in drops, hoods, tops, and even out of the saddle a few times.

asgelle
12-08-07, 06:23 PM
Be careful testing on a 20 minute climb though. You'll end up overestimating your FTP because the climbing position is more efficient. You can't ride like that on the flats. I did a rolling course today and spent time in drops, hoods, tops, and even out of the saddle a few times.

There is no evidence that grade or position affects efficiency, which could never be determined by a power meter alone anyway. Some people are able to produce higher power on climbs than on the flats, but there are also those who show the reverse. The difference is related to neuromuscular effects and how individuals respond to differences in inertia, not efficiency.

cslone
12-08-07, 06:25 PM
Yep, I can hold a decent amount higher wattage on the flat than on a climb. Have never been able to figure that one out. Maybe being on the rivet as opposed to scooting back?

ericm979
12-08-07, 07:54 PM
I tried doing a 20 min test this week on the flat (actually slightly rolling, there's no true flat here that isn't interrupted with stoplights). It sucked dead gerbils. I could barely get my HR up to the mid 160s and my power was well below what I know I can do, and did today.

It could have been because I was cold or because I'd done weight lifting the previous two days, but I think in my case that a large part of it is mental. I'm almost always up for going hard on a climb, but I really have to be in the mood to go hard on flat ground, especially by myself. It's one of the things I need to work on.

waterrockets
12-08-07, 09:41 PM
There is no evidence that grade or position affects efficiency, which could never be determined by a power meter alone anyway. Some people are able to produce higher power on climbs than on the flats, but there are also those who show the reverse. The difference is related to neuromuscular effects and how individuals respond to differences in inertia, not efficiency.

Yeah, I guess it's best to test on terrain similar to your common racing terrain, or important events.

Duke of Kent
12-08-07, 10:31 PM
I tried doing a 20 min test this week on the flat (actually slightly rolling, there's no true flat here that isn't interrupted with stoplights). It sucked dead gerbils. I could barely get my HR up to the mid 160s and my power was well below what I know I can do, and did today.

It could have been because I was cold or because I'd done weight lifting the previous two days, but I think in my case that a large part of it is mental. I'm almost always up for going hard on a climb, but I really have to be in the mood to go hard on flat ground, especially by myself. It's one of the things I need to work on.

If I haven't done any sort of hard effort the day before a test, or hard interval day, I'm pretty much dead in the water. I can't get the HR up and my power is miserable. So, I rarely do a REAL recovery day. I might tool around for 2hrs but I'll almost always throw in a 10min segment to open it up. Never maximum effort, just get moving and elevate the HR and wattage enough to feel a little burn in the legs, then do the rest of the ride nice and easy. It doesn't drain me and I feel great afterwards, and I'm ready for the real workout the next day.

NomadVW
12-08-07, 11:52 PM
20 minutes.. blech. MAP takes me 11... (I'll let you all know how much I rock that one on Tuesday).

That being said - power drop off in the distribution is going to be very hard to use if you weren't riding the whole time @/near your threshold. On the other hand, if you're riding a specific intensity for a workout, that will additionally skew the results because - well.. gee - the closest power drop off will be at the top of your workout intensity.

What would I do? I would do a test only intended to help me find FTP. You could do like WR said and pace your FTP 1-hour test @ 270. You could do a 20 minute max power test (and a 5 minute, and probably a 1 minute too) and use Monod's - I've found the Monod method very repeatable/reliable. Or you could MAP test (ala www.cyclecoach.com) and use the 75-78% value of MAP. The only one I don't like is the 1 hour test, because - IMO - you need to be in "race fresh" mode to effectively get a good number from a 1 hour TT.

Just my take.

waterrockets
12-09-07, 09:31 AM
Yeah, and a 1-hour test is disruptive to any other training going on that week.