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RShantz 05-17-15 03:02 PM

Power at specific cadence
 
Is there any software out there that estimates FTP for a specific cadence or range of cadence? I'm a spinner (like to average 110) but was at an event yesterday where I had to mash (under 80) for a good bit. My power numbers were a lot lower than I would have expected while mashing. This tells me I need to do some low cadence work, but I'd love to quantify if possible.

Silvercivic27 05-17-15 03:06 PM

Umm...it doesn't really work like that...

RShantz 05-17-15 03:43 PM


Originally Posted by Silvercivic27 (Post 17812984)
Umm...it doesn't really work like that...

The data I'm asking for is there. Maybe I didn't ask the question the right way as the data I'm after really wouldn't be FTP, but your average watts for specific cadence is there. I just don't have of the software to extract such data.

I'd imagine this data would be valuable to the pros. They would need to know (from past performance) where they generate the most power. I'd like to know this so I know exactly how much worse my power is at certain cadences so I'll know better how to train.

Silvercivic27 05-17-15 03:52 PM

Your question really does not make any sense. You can make whatever power you want at whatever cadence you want. If you're asking at which cadence you are the most efficient, that is a much more complicated question and I don't think there's any software out there that can just figure that out for you. The Pioneer powermeter will analyze how even your pedal stroke is but that is totally different than asking what cadence is most efficient for you from a physiologic standpoint.

RShantz 05-17-15 03:59 PM

I'm thinking it would be pretty easy to analyze what I'm asking. If you rode 300 minutes with a normalized power of 250W, I'd like to know the power distribution by cadence. Something like:
Cadence 70-75, 50 Minutes, 200W average
Cadence 75-80, 40 Minutes, 220W average
Cadence 80-85, 30 Minutes, 240W average
Cadence 85-90, 80 Minutes, 270W average

You get the idea.

popeye 05-17-15 04:03 PM

Power = rpm * torque.

popeye 05-17-15 04:05 PM

Get GoldenCheetah, it's free.

Silvercivic27 05-17-15 04:05 PM

I think I know what you are asking for, but again, you can make whatever power you want at whatever cadence you want. That is why what you are asking for is not very useful and probably why no program measures that.

bikepro 05-17-15 04:45 PM

1 Attachment(s)
Something like this?

http://bikeforums.net/attachment.php...hmentid=452063

asgelle 05-17-15 04:53 PM

Principles of training: Overload, Progression, Specificity.

Where were you lacking?

Drew Eckhardt 05-17-15 05:06 PM

2 Attachment(s)

Originally Posted by RShantz (Post 17812976)
Is there any software out there that estimates FTP for a specific cadence or range of cadence? I'm a spinner (like to average 110) but was at an event yesterday where I had to mash (under 80) for a good bit. My power numbers were a lot lower than I would have expected while mashing. This tells me I need to do some low cadence work, but I'd love to quantify if possible.

Golden Cheetah will give you a 3d plot of cadence vs. power

http://bikeforums.net/attachment.php...hmentid=452068

and do quadrant analysis with a movable power curve (it defaults to critical power, where mine is 220 Watts)

http://bikeforums.net/attachment.php...hmentid=452069

It will also export rides as Comma Separated Value files that are trivial to parse and manipulate using the programming language of your choice.

Drew Eckhardt 05-17-15 05:08 PM


Originally Posted by Silvercivic27 (Post 17813144)
I think I know what you are asking for, but again, you can make whatever power you want at whatever cadence you want. That is why what you are asking for is not very useful and probably why no program measures that.

Where power = torque * rpm, torque becomes infinite as rpm approaches zero. Eventually you run out of physical strength, and at some point you're not pushing fast enough to recruit sufficient muscle fibers.

_Training and Racing with a Power Meter_ tells the tale of a racer who was dropped every time he spent over 5 minutes at his FTP but cadence below 70 RPM. Lower gears fixed that problem.

Silvercivic27 05-17-15 05:15 PM

Well, I stand corrected but I don't think your plots are measuring what the OP is asking for because he also wants the time spent at each cadence. I don't use Golden Cheetah, I guess that's why I didn't know about it.

Silvercivic27 05-17-15 05:19 PM


Originally Posted by Drew Eckhardt (Post 17813293)
_Training and Racing with a Power Meter_ tells the tale of a racer who was dropped every time he spent over 5 minutes at his FTP but a cadence below 70 RPM. Lower gears fixed that problem.

I guess but different people are different and I think are efficient at different cadences. Trying to address which cadences you are most efficient at is a different story. There are also different issues in racing where different cadences are advantageous or not, such as crit racing vs a TT. I spent years trying to increase my cadence, but I don't think that was the right thing to do in retrospect.

RChung 05-17-15 05:28 PM


Originally Posted by RShantz (Post 17812976)
Is there any software out there that estimates FTP for a specific cadence or range of cadence?

No, nor should there be.

Optimal cadence and power data

The components of power

RShantz 05-17-15 05:29 PM


Originally Posted by bikepro (Post 17813234)

Exactly. Is this Training Peaks premium?

asgelle 05-17-15 05:30 PM


Originally Posted by Silvercivic27 (Post 17813317)
I guess but different people are different and I think are efficient at different cadences.

But only within a very limited range; from about 60-65 rpm. Then again, what does efficiency have to do with anything? The issue is fatigue. (or are you using efficiency in some new undefined way?)

RShantz 05-17-15 05:31 PM


Originally Posted by Drew Eckhardt (Post 17813287)
Golden Cheetah will give you a 3d plot of cadence vs. power

http://bikeforums.net/attachment.php...hmentid=452068

and do quadrant analysis with a movable power curve (it defaults to critical power, where mine is 220 Watts)

http://bikeforums.net/attachment.php...hmentid=452069

It will also export rides as Comma Separated Value files that are trivial to parse and manipulate using the programming language of your choice.

Thanks. This is a little harder to read than what Bikepro posted, but it is 3d with time. This is exactly what I was trying to explain in my original post.

RShantz 05-17-15 05:33 PM


Originally Posted by Silvercivic27 (Post 17813144)
I think I know what you are asking for, but again, you can make whatever power you want at whatever cadence you want. That is why what you are asking for is not very useful and probably why no program measures that.

I don't think you know what I was asking for. This info is indeed valuable if you start using a cadence outside of your comfort zone.

RShantz 05-17-15 05:49 PM


Originally Posted by Drew Eckhardt (Post 17813293)
Where power = torque * rpm, torque becomes infinite as rpm approaches zero. Eventually you run out of physical strength, and at some point you're not pushing fast enough to recruit sufficient muscle fibers.

_Training and Racing with a Power Meter_ tells the tale of a racer who was dropped every time he spent over 5 minutes at his FTP but cadence below 70 RPM. Lower gears fixed that problem.

This is what I'm afraid I experienced. At about mile 50 there was a 5 mile climb averaging 5% (obviously some of this climb has short stretches much higher than 5). Then a flat of about 2 mile, then a 3 mile climb averaging over 9% - again with segments well over 9%. I just didn't have enough energy left to spin up the last 3 miles so I had to use a lower cadence. But as I used the lower cadence, my power just kept decreasing. I have very low gears, but at these grades it's tough for my fitness level. To me I've got 2 ways to fix the problem: 1)increase fitness & threshold so I can spin up the climb at mile 60 or 2)improve power sustained power output at lower cadence. I'll probably just work on both.

gregf83 05-17-15 05:57 PM

1 Attachment(s)

Originally Posted by RShantz (Post 17813132)
I'm thinking it would be pretty easy to analyze what I'm asking. If you rode 300 minutes with a normalized power of 250W, I'd like to know the power distribution by cadence. Something like:
Cadence 70-75, 50 Minutes, 200W average
Cadence 75-80, 40 Minutes, 220W average
Cadence 80-85, 30 Minutes, 240W average
Cadence 85-90, 80 Minutes, 270W average

You get the idea.

That data and all the pretty graphs Golden Cheetah or any other software generates isn't going to tell you anything unless it's somehow couple with your perceived exertion at those cadences. On a given ride if I'm warming up or going easy my cadence will naturally be lower than if I'm doing a threshold interval. That doesn't in any way imply, however, that I'm not capable of putting out power at lower cadences.

I think you're going to need to do some of your own tests. One of the interval sets I like to do is 6 x 5 x 1 @ 106-108% of FTP. That's 6 - 5 minute intervals with 1 minute rest between intervals. A few yrs ago I tried varying the cadence during the intervals. I didn't notice a big difference and have attached a plot of my data. The blue trace is cadence which I varied from 77 to 100 RPM. I think my HR was a little higher on the high cadence interval but it's a hard to tell how much as my HR normally goes up from intervals 1 through 6. Yesterday I did a similar set and wasn't paying attention to cadence and it was around 94-95 with an avg power of 310W, so I assume that's my preferred cadence at that power. I have no doubt that I could manage the same power, however, at anything from 80 to 105RPM.

http://www.bikeforums.net/attachment...hmentid=452078

RShantz 05-17-15 06:53 PM


Originally Posted by gregf83 (Post 17813404)
That data and all the pretty graphs Golden Cheetah or any other software generates isn't going to tell you anything unless it's somehow couple with your perceived exertion at those cadences. On a given ride if I'm warming up or going easy my cadence will naturally be lower than if I'm doing a threshold interval. That doesn't in any way imply, however, that I'm not capable of putting out power at lower cadences.

I think you're going to need to do some of your own tests. One of the interval sets I like to do is 6 x 5 x 1 @ 106-108% of FTP. That's 6 - 5 minute intervals with 1 minute rest between intervals. A few yrs ago I tried varying the cadence during the intervals. I didn't notice a big difference and have attached a plot of my data. The blue trace is cadence which I varied from 77 to 100 RPM. I think my HR was a little higher on the high cadence interval but it's a hard to tell how much as my HR normally goes up from intervals 1 through 6. Yesterday I did a similar set and wasn't paying attention to cadence and it was around 94-95 with an avg power of 310W, so I assume that's my preferred cadence at that power. I have no doubt that I could manage the same power, however, at anything from 80 to 105RPM.

Agreed. I'd need to test the data on some intervals & compare to RPE. I'm with you that I think I'd be OK with a cadence as low as 80, but I'm thinking I've got problems if it drops much lower. That's what I'm wanting to quantify & work to improve at least for short durations.

rm -rf 05-17-15 06:54 PM


Originally Posted by RShantz (Post 17813380)
This is what I'm afraid I experienced. At about mile 50 there was a 5 mile climb averaging 5% (obviously some of this climb has short stretches much higher than 5). Then a flat of about 2 mile, then a 3 mile climb averaging over 9% - again with segments well over 9%. I just didn't have enough energy left to spin up the last 3 miles so I had to use a lower cadence. But as I used the lower cadence, my power just kept decreasing. I have very low gears, but at these grades it's tough for my fitness level. To me I've got 2 ways to fix the problem: 1)increase fitness & threshold so I can spin up the climb at mile 60 or 2)improve power sustained power output at lower cadence. I'll probably just work on both.

Or 3) Get really really low gears. But it's a race, you can't go too slow.

A long 9% grade is pretty steep to be able to spin up. For instance, on this bike speed calculator: rider 150 pounds, bike 16 pounds, in the drops, 9% grade: 8.2 mph is 270 watts. That 8.2 mph is 87 rpm on a 34-28 low gear.

bikepro 05-17-15 07:05 PM


Originally Posted by RShantz (Post 17813342)
Exactly. Is this Training Peaks premium?

No. It's from the BikePro application that I developed. If you're interested, here's a link to the web site.

BikePro

gregf83 05-17-15 07:08 PM


Originally Posted by RShantz (Post 17813541)
Agreed. I'd need to test the data on some intervals & compare to RPE. I'm with you that I think I'd be OK with a cadence as low as 80, but I'm thinking I've got problems if it drops much lower. That's what I'm wanting to quantify & work to improve at least for short durations.

For it to be meaningful though you need to do a specific test at a particular cadence. Just collecting the data from a random ride and examining power in different cadence bands won't answer your original question.

I think you'll probably surprised at the power you can put out even as low as 50-60RPM. I occasionally do low cadence work and don't have any problem putting out between threshold and VO2Max power at 50-60RPM. On a recent trip to Spain I got stuck going up a 20% climb at 54rpm and 480W (briefly) because I was overgeared.


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