Results after 10 sessions I understand to mean proof that PC can improve your power delivery in 10 sessions.

developing a pattern of force is not the same thing. I agree that you can develop the pattern of force in a short time.

I believe that you need much longer to develop the required muscles do deliver the force to be superior to that delivered during the previous pedal stroke technique.

---

----------------------------------------------------------------------------------
TriRaceBook.com
.
Hawaii Qualification Analysis

Ding, ding, ding, ding, ding!!! We have a winner!

Now do you see why I was telling Frank he's putting the cart before the horse?

Frank...you keep ASS-U-MING a speed variation (using wrong numbers, I might add) and then calculating how much power would need to be added to get that acceleration. However, you also need to have a matching deceleration for that speed variation as well. Aero drag and rolling resistance aren't enough...Hence my question about why you are applying the brakes so much ;-)

You need to assume the power variation and THEN calculate the speed variation. Then you can play all you want with the energy calculations. THAT puts the horse back in front of the cart.

---

http://bikeblather.blogspot.com/

I'm "all in" on the doc ;-)

Here, I'll finish my statement for you: "You on the other hand...have nothing to lose" :-)

---

http://bikeblather.blogspot.com/

Rather than flailing about with all this erroneous gobbledygook, I suggest that you spend some quality time with the following equation:

http://www.biketechreview.com/archive/appa.pdf

Code it up and play around with it. That's what I've done in the past. THAT's why I'm NOT, as you say, "just stating what I believe".

Do the work and learn the subject instead of continually demonstrating your ignorance. You actually might just learn something.

---

http://bikeblather.blogspot.com/

You can do it that way if you want to. My way is simpler as it is simply looking at the work required to change the speed from x to y, whether one is in a vacuum or in water. The drag forces needed to be overcome just to maintain speed do not interfere with the analysis. It simply looks at the energy cost of the speed fluctuation and nothing else. If you know the speed fluctuation, you know the energy cost of the fluctuation. If you know the frequency of the fluctuation, you know the power cost of the fluctuation. You can do the analysis your way if you wish and you should come up with the same answer. Do it and tell us what you get. I look forward to seeing your answer, and your work should the answer be different than mine.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Well there you go - and since the hypothesis that a more tangential pattern of force application is optimal is based on purely physical (as in physics) considerations, it therefore follows that any study that can induce such a pattern is a valid test, regardless of how long it takes to produce such an "improved" pattern.

Once again you've convincingly proved that ignorance truly is bliss :-)

Sure, you're way is simpler...but it's still wrong. It's no better than just picking numbers out of thin air...which is really all you've done.

You don't "know the speed variations" until after you've calculated them using the given power conditions and the retarding forces (including inertial terms).

---

http://bikeblather.blogspot.com/

Yeah I remember. And there was some discussion of it on the Wattage list as well, wasn't there? Interesting, and yeah, that's why I believe you, because I have seen the plots of power vs speed as they're oscillating, and you're right, faster oscillations should make the power/speed variations smaller because at the limit of infinitely small variations, you're at constant speed.

---

---
justin

It is difficult to get a man to understand something when his salary depends upon his not understanding it. -Upton Sinclair

Sure I know the speed variations, Dr. Coggan has calculated them for me and told us what they are. That, along with the frequency, is all I need to know to calculate the power cost. According to his numbers for the scenario used the cost is over 140 watts. The math don't lie. Do it your way and see what you get.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

We don't know that the pattern of the force application in this study was more tangential. All they measured was the relative contribution in the various quadrants, isn't that correct? More contribution does not necessarily mean more tangential. They are not the same. I would expect such to occur but it is not obvious from this study that it was measured and confirmed. Further, it appears to me that there was some benefit between the goups but that the "benefit" did not reach statistical significance at the 0.05 level. That does not mean that they would not have reached statistical significance if they had more people or more time. I'll bet they could have shown some coordination changes in 2 sessions. They would have in one session if they did their testing on PowerCranks. Your contention that 5 weeks (and 10 sessions) is enough time to evaluate a product / training method that anecdotal data seems to suggest that it takes many more weeks or months to see benefit is laughable. It might be enough time for some things, it might not be for others.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Sure it is. It is the work required to accelerate the rider from one speed to another. It ignores the wind resistance.The formula doesn't care if the rider is riding in a vacuum and applying the brakes regularly or if the rider is pedaling irregularly and wind resistance is slowing him/her regularly. If the rider got to a particular speed and stayed there this additional power number would be zero. Each time the rider slows and accelerates though it costs additional work. This formula calculates that additional work. It is that simple.

The really cool thing about this formula is that now it is easy to calculate the losses associated with pedaling, especially the losses associated with the pumping action of the thighs specifically. I will do that soon. I look forward to that debate also.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Typical of many such "studies, five weeks isn't long enough to figure out how to use PCs, let alone see if they do anything for you.

---

Cousin Elwood - Team Over-the-hill Racing
Brought to you by the good folks at Metamucil and Geritol...

Now that I understand what you did, I will revise my previous OK. My new answer,

No, the number of iterations are not important, not when it is only over one cycle. There will be no convergence. 100 iterations per cycle for 10-100 cycles should give you the steady state answer for most scenarios.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

I see you're conveniently ignoring the -145.81J difference in KE in the second half of the given cycle.

Damn. With math skills like that, I'd be surprised if you can even balance a checkbook :-)

---

http://bikeblather.blogspot.com/

I am not ignoring that. That difference is, of course, this half of the speed change is lost as heat and involves no energy input requirement (isn't that what we are trying to analyze?). If it were not lost as heat then there would be no need to put the extra energy/work back in on the acceleration to make it back up. If the speed is constant there is no excess heat loss nor need to make it back up. The question is not what is the excess heat loss but what is the excess power requirement. So, it is ok to "ignore" the heat loss side of the question for this analysis. Why would you think otherwise?

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Here is another way to look at this. How much work does it take to accelerate an 85 lb object from 11.1378 m/s to 11.2908 m/s in 0.5 seconds.

The acceleration 0.153 m/s in 0.5 seconds or 0.306m/s/s. This requires a force for the 85 kg object of 26.01 N

Work is force through a distance. If the average speed is 11.2 m/s this means the object is acted upon for 5.6 meters with a force of 26.01N resulting in 145.6 joules of work being done just to accelerate the object. Pretty good agreement.

But, we are putting in 150 joules. If there were no air resistance we would expect to put an extra 150 joules of energy into the system and see an extra 150 joules added to the KE. But, instead we only see 146. That means to me the variation is costing 4 joules due to the non-linear aspect of the resistance, or 4 watts, at a frequency of 1/sec,

This gets us back to the same number we had many pages ago on this thread, post 98. a loss of about 4 watts out of 300. In retrospect, that number was correct because it looked at the average speed cost using the work/energy principle. That, I believe, was the "easy" correct solution to the problem.

So, it gets us back to arguing whether 4 watts is insignificant or not. I submit it is "small" but not insignificant such that there is potentially more to be gained by changing pedaling pattern than by, say, getting a lighter bicycle. The "cost" be smaller for more normal pedaling patterns but, again, how small does something have to be to be "insignificant"?

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Let's see if I can be clearer: I set up the spreadsheet with 1000 rows, each representing 1 msec. I then solved for the speed that result in no net acceleration when the power was 600 W for the first 500 msec, then 0 W for then next 500 msec. Convergence was indeed achieved (in less than 10,000 iterations), i.e., the initial and final speeds were within 0.0000001 msec of each other. Increasing the number of iterations/requiring a higher degree of convergence would only change the answer out beyond the 7th decimal place.

Your claim is refuted by the fact that the authors of the study in question found that training with SmartCranks for 5 wk did indeed change the pattern of force application when pedaling with normal cranks.

I would have done it differently but gotten the same result. I would have started at a certain speed and then changed to the scenario and calculated until the speed didn't change. You solved for that speed. I accept that your numbers are correct. I didn't understand how you did it in one cycle. As long as the increase in speed when the power is "on" equals the decrease when it is "off" the system is in a steady state. Your numbers meet that criteria.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Again, 145.81 J, not 145.81 W. The power used to accelerate the bike+rider during that 0.5 s period is 291.62 W. However, this is not - again, not! - the power 'cost' of constantly re-accelerating the bike, as 100% of that energy input is stored and then released during the coasting period. The additional power that must be generated to constantly speed up and slow down as in this scenario is <0.14 W, i.e., a rider producing 600.28 W for 0.5 s then coasting for 0.5 s will go just as fast as a machine producing a perfectly constant 300 W.

Finally!

I disagree. It appears to me the cost of this scenario is about 4 watts. You are putting 150 joules in and getting 145.8 joules of benefit. You are losing 4 joules of energy each cycle. At a frequency of 1 per second that is 4 watts.

If you have another explanation to explain the disappearance of the 4 joules I would love to hear it.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Aren't we losing power to the efficiency of the powertrain as well? I lost track of where we were on the argument and I can't remember if that's bee accounted for in the 150 joules -> 145.8 joules you're talking about.

If that's already been accounted for, ignore me...that shouldn't be tough! ;-)

---

--------------------------------------------------------------------
"Lemond is cycling's version of Rev Jessie Jackson." -johnnyperu 5/18/07
"Just because I suck doesn't mean my bike has to" -rickn 9/2/08

Let me ask you the question this way. Your calculation put in 300 watts but you are only seeing 291.62 watts being used to go accelerate the bicycle. Where are the other 8+ watts going such that the rider actually "only" loses <0.14 w. We must account for all the energy. where is it going? My analysis says the cost is 4 watts. Your analysis above leaves over 8 watts unaccounted for. Where are they?

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

I don't think so. His spreadsheet, I believe, used power to the wheel. At least, that is what I have been assuming.

---

--------------
Frank,
An original Ironman and the Inventor of PowerCranks