Doge

Force is mass X acceleration
Work is force over distance
Power is work per time

But as a competing cyclist while studying for my EE in early 80s I learned the cute 2D calculations rarely matched reality and we spent hours in both the calculus and physics classes (with a CalTech prof) working on this stuff, just to throw our collective hands up and say it is like calculating where all the billiard balls will go. I've since just tested a bunch. A whole bunch. We are now very old school. I just use the principles, discuss it with junior (who will be USAFA guy - just re reminding everyone and - nobody in this family could not ace any college calc or physics test - in the day) and ask what he prefers and go with that. It is not ignorance, it is giving up that this stuff can be calculated beyond the level humans can feel it.

beatlebee 

Yeah, as I mentioned before, most people are used to the linear definitions of work (rather force *times* distance (but really it is defined in terms of a dot product, but never mind) and power, but the angular definitions would make more sense in this application. But to your other point, I know all too well that most "simple" problems are rarely that.

Doge

My kid's TT chain-ring is not round. And it has offsets / indexes for where max radius is. So, I have no equation for the ring - it is not a circle or an ellipse, he uses human legs with slippery joints to move it.

I mean - how does anyone really calculate that stuff.

RChung

Bingo. Yet many look at rpm while ignoring torque (or pedal force).

You were crediting Dave with something that I'm sure he wouldn't claim himself. Andy developed those ideas before WKO or TrainingPeaks (or CyclingPeaks, the precursor of TrainingPeaks) existed.

Doge

Dave said to me something close to - "I'm a mathematician and I wrote the algorithms for WKO and Training Peaks". He also said to me - "I worked with Andy and ..."

That was good enough for me for a BF post.
I can't see where Andy in print said otherwise.

I assume you know Andy - ask him.

I think Dave is an honest fair guy who I first met when I took my 10 year old to him. He charged us nothing. He later fit a friend who found him independently. I have bumped into him on Palomar as he had his UC Irvine cycling team out there and we were training. We just last year went back - for a fitting. I have only been with Dave 4-5 times, but have no reason not to believe him, but nothing close to proof he wrote anything, other than seeing a real old spreadsheet and his garage with real genuine UCI World champion jerseys in it (his garage).
Oh - he also helped my kid get faster not pedaling in circles, but much harder to do calculations on.

RChung

Sigh. I don't have to. I was there when Andy came up with these algorithms and models. He did them before WKO and TrainingPeaks existed. If Dave worked on them, that's an admission that he came after. I'm sure you misunderstood what he was saying. That's cuz you weren't there. I was. Next you'll probably say he came up with the name "normalized power."

Doge

I was just reporting. I would be curious to hear what Andy said Dave's roll was. The power thing is not something we follow except for periodic eWang. We don't train or race with it. Do you have anything that contradicts my post that max power happens in the 90s for road racers?

Doge

Are you doubting what I reported? And if so, why would that be?

asgelle

Yeah, but have you ever in your life ridden a fixed gear?

RChung

Max power? Sure. But it's pretty clear you know nothing about power, so explaining the evidence almost surely won't help.

Hmmm. Yes. And that would be because of two things: first, I know for a fact that Dave didn't come up with those algorithms, so either you're misreporting, or else he lied to you. Given the choice between someone who I've never met and know nothing about being a liar and you being wrong, on top of the evidence of your body of posts? I'm leaning toward thinking you're the one in error.

Those were great days.

69chevy

No.

Cadence does not determine power.

It takes exactly the same amount of power to move a bike and rider regardess of cadence.

spdracr39

Andrew Coggan

No, that would be me (not to dis any of Dave Jordaan's accomplishments/contributions to the sport of cycling).

Andrew Coggan

You were? Damn, and here I thought I was alone in my old office...

Doge

Thanks for that. I explained what I heard. I backed down. I'll re-ask Dave later as to what I was supposed to hear. We are using Dave for fitting and TT technique. That has been going well.

topflightpro

I'm not well-enough informed about power determination to offer any commentary on how cadence factors into power.

BUT, I often find it easier to maintain a set power at a higher cadence. When doing intervals and targeting a set power output, I find that I am better able to maintain that power by shifting to an easier gear and spinning faster than going to a harder gear and pedaling slower. This comes into play when doing intervals outside, and I hit an uphill section.

Heathpack 

So I never saw a clear answer to this question in this thread. When I first read it, I thought it would be easy & obvious. Yes, you put out higher power at higher cadence, provided you maintain the same torque applied to the pedals. I commonly do this when I have a power target to meet and a cadence to stay above- just pedal faster & I'll output more power.

I had a conversation recently with a more experienced cyclist who was insisting to me that if cadence increased, torque had to decrease. Lol, he would not hear otherwise, even though I was telling him that I manipulate these two variables all the time, intentionally, when I ride. Interestingly he has an (IBike) power meter so presumably can look at power in real time just like I do. So it was strange to me that he has not yet realized that you can in fact increase cadence and torque at the same time to produce more power.

RChung

Here's cadence and crank torque for the same rider in three different types of races.

big chainring 

Is this going to be on the test?

wphamilton

I can't say what he's thinking, but it seems to me that cadence abstracts the question that matters by one level further. The amount of torque your muscles can supply repetitively and recover in between. You might derive that from cadence (knowing some other factors) but it's one step removed and the torque may be a more consistent factor. So I think he has a point.

Doge

In my 20s I was working on this thing called the "Spin Coach". It was for individual leg training to teach you to spin better/apply power through the entire stroke. The idea was you wouldn't have to torque as much if you did it over a longer arc.
Anyway the question is in a .75 (rough numbers) sec pulse cycle (one RPM) are you better just jamming the down stroke in a .15 only and "resting" the other .60 sec, or trying to use a more smoother, lower torque .30 power cycle and less rest. I know different muscles are used.

Anyway after years of being smooth, and teaching my 5 yo now 17 to be smooth - I think that is less than ideal for max power. Seems stomping pedals is more powerful, although more fatiguing. Smooth still seems the best for going long.

intransit1217

I enjoyed watching the Graeme Street video. I would like to have seen him visit the radical ends of his spectrum to get a better picture. IE: Staying in that low gear and taking it as high as he could go, as well as putting it in his biggest gear and seeing how long he could hold it.

I'm trying to follow this to understand better why I feel more efficient in a 44x16 than a 50x11, frex.

Last night during trainer session, last exercise was three 15 sec sprints, 1 min rest between, and he had us accelerate on the last one. Just for giggles today, I plugged in my garmin to see where I spun out.

180 rpm in a 34x16.

I will never do that again because it is too hard on my ligaments. And. I doubt I was generating any usable power/ torque/ watts that high.

*I do not have a watt meter. But I'm beginning to see the value.

Sy Reene

and you're staying in the same gear? Of course pedaling at 100 rpm would be more power than at 85.

f4rrest

Like a flashback from Econ 101 -- the red dotted look like indifference curves.

RChung