Page 13 - pealling push up push down

07-12.-2005, 08:32 AM

#181

n crowley

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Join Date: Jul 2003

Location: dublin ireland

Posts: 412

Re: pealling push up push down

Quote:

Originally Posted by Fday

Somehow I stumbled across this thread and felt I had something to offer. Some of you know me from other forums, most notably Slowtwitch. To those who do not know me I am the inventor of PowerCranks. PowerCranks are independent cranks that force the user to, at a minimum, completely unweight on the upstroke. Our data suggests that the typical user will gain 40% in power, at least for reasonable distances (40K or so), after 6 to 9 months of exclusive use (it takes quite awhile to change things). Independent studies have shown cycling efficiency improvements of 10% in only 6 weeks or 3 times a week use. So, it does seem from this data that the "circular" pedaling style can make a difference in regards to to power potential of the athlete.

But, that is not what I am mostly interested in talking about here. It is clear to me that most of you don't have a clue where cycling power and forces on the pedals are coming from. Those who think style doesn't make a difference cite the Coyle study, which has many significant flaws when it comes to showing what these people purport that it shows. They say that the stronger cyclists don't pull up and that the only thing that matters is how much one pushes down. B.S.

Let's look at the basics of where these forces come from. On the downstroke, there are two sources of downward pedal forces. The pushing muscles are, of course, one. But the passive weight of the thigh is another. When the thigh is lifted on the backstroke, potential energy is put into it which is recovered on the downstroke. If Coyle did not account for the mass differences of the thighs in the riders in his study (which he did not) he cannot say who is pushing harder and who is not.

By the same token, as long as the backward forces on the upstroke are less than those that would come from a flacid leg (which they are in everyone) then everyone is "pulling up" on the backstroke, they just are not doing so enough to completely unweight the pedal. But, everyone is putting the same amount of potential energy into the upward moving thigh. This energy must come from muscles pulling the leg up or from forces of the downward moving leg being diverted from the wheel to push the leg up, or a combination of the two. A person with a more massive thigh must pull up "harder" to achieve the same negative force on the pedal as someone with a smaller thigh even though if one were to look just at the pedal forces one would think he was not pulling up at all or equally. While he may not be driving the bicycle directly at this point in time he does get this energy back on the downstroke (when the potential energy he puts in is recovered) so it does contribute to driving the bicycle, whether it is obvious or not.

Anyhow, I thought I would try to clarify this misconception of what pushing and pulling means and how it relates to cycling efficiency.

Frank Day
PowerCranks

Frank, time trials and pursuits are all about pedal power and aerodynamic position, what power can a powercranker apply to the pedal between 11 and 1 o'clock when he is in a good aerodynamic position with his back parallel to the ground?

07-12.-2005, 12:21 PM

#182

Fday

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Join Date: Dec 2005

Location: California

Posts: 669

Re: pealling push up push down

Quote:

Originally Posted by whoawhoa

So why does it make a difference weather your upward-moving thigh is pulled up by that leg or by the downward force of the opposite leg?

I'd love to believe in your product, because a 40% gain would turn me (and many other average competive cyclists) into tour-winning shape.

Well, there are a couple of reasons. First, if the pushing muscles are not pushing so hard they could be operating at a more efficient range and able to go longer. It is clear if we want to ride 100 miles as opposed to 10 we must back off on the forces or our legs just can't do it, so we slow down. By evening out the energy input amongst more muscles we should expect them all to perform better and longer, if they have all been equally trained. Training with the PC's forces the equal training of all the necessary muscles.

Regarding the 40% improvement, this is not all coming from just pulling up more. I believe some of it (perhaps the majority) is coming from learning to anticipate the pedal direction changes resulting in improved coordination and more tangential forces along the pedal circle. (This has yet to be proved.) If the forces are redirected to be more tangential one is getting more power from exactly the same muscle contractions, just timed slightly differently. All of these changes can result in improvement and when they are added together the improvements can be large. Not everyone sees 40% improvement. Some see less but others see more. And, it takes time, it doesn't occur overnight. But, 40% is in line with what most users report back to us. But, don't take my word or anyone elses. We offer that 90 day moneyback guarantee and if you haven't convinced yourself they are worth the money in that time send them back and all you have lost is postage. Most are convinced in about 2 weeks I believe.

Frank

07-12.-2005, 12:41 PM

#183

Fday

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Join Date: Dec 2005

Location: California

Posts: 669

Re: pealling push up push down

Quote:

Originally Posted by n crowley

It is rare that a new user can get on and even pedal in the aero position. Occasional users are riding aero within a month or so. It probably takes most new users a 6 months to a full season of hard work before they can get to close to their previous aero position and pedal with power for 40 K or so. So, yes they can but it takes time and hard work.

PC's require a certain dedication if you are going to see the big benefits. If you are not willing to do the work forget them.

Frank

07-12.-2005, 01:00 PM

#184

mitosis

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Join Date: Jun 2004

Location: east coast australia

Posts: 1,338

Re: pealling push up push down

Quote:

Originally Posted by Fday

Ha Ha Ha Ha Ha.........................

07-12.-2005, 08:13 PM

#185

n crowley

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Location: dublin ireland

Posts: 412

Re: pealling push up push down

Quote:

Originally Posted by Fday

Coyle's knowledge of pedalling is very limited but so also is yours. Unweighting is beneficial but unweighting and drawing back between 5 and 9 o'c has even more to offer. With practice it soon happens naturally in keeping with the linear style of your other leg. Recent testing that I have been doing surprised me by demonstrating that in addition to the unweighting effect you are adding lbs of torque to the crank without any effort through the lower dead spot area. This is in addition to the maximum power your other leg is applying as it moves through the upper dead spot area. Once you have the knack, it can be done from day one with normal pedaling equipment. Except for the unweighting effect, pulling up has nothing to offer and unweighting can happen naturally by simply raising your leg as you do when climbing a stairs. The explanation for the effectiveness of this special technique is that you have two independent resistance sources for both the drawing back and main power application. There is more to pedalling science than the natural circular or mashing styles.

09-12.-2005, 12:17 PM	#186
Fday Registered User Join Date: Dec 2005 Location: California Posts: 669	Re: pealling push up push down Some people have brought it to my attention that I may have offended some of you when I posted: "most of you don't have a clue where cycling power and forces on the pedals are coming from". It would have been perhaps more politically correct to say "It SEEMS most of you have forgotten about gravity"." Gravity plays a role in determining pedal forces. If you do not account for gravity then your analysis is incomplete. My apologies to anyone who was offended by my tone. Frank

09-12.-2005, 08:28 PM

#187

mitosis

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Location: east coast australia

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Re: pealling push up push down

Quote:

Originally Posted by Fday

Some people have brought it to my attention that I may have offended some of you when I posted: "most of you don't have a clue where cycling power and forces on the pedals are coming from".

It would have been perhaps more politically correct to say "It SEEMS most of you have forgotten about gravity"." Gravity plays a role in determining pedal forces. If you do not account for gravity then your analysis is incomplete.

My apologies to anyone who was offended by my tone.

Frank

I can't speak for anyone else but that was nothing. You offended me by thinking I (or anyone else with a little common sense) would believe your claim of a 40% increase in power.

You must be having a great laugh. I know I am.

10-12.-2005, 12:59 AM	#188
n crowley Registered User Join Date: Jul 2003 Location: dublin ireland Posts: 412	Re: pealling push up push down [QUOTE=Fday]Some people have brought it to my attention that I may have offended some of you when I posted: "most of you don't have a clue where cycling power and forces on the pedals are coming from". And that in many cases is correct because as long as they can stomp on the pedals and use their PM, they don't care. If they did, pedalling would not have remained in its stagnant state over the past 50 years.

10-12.-2005, 01:05 AM

#189

jerryz

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Join Date: Dec 2004

Location: PHX, AZ

Posts: 93

Re: pealling push up push down

Quote:

Originally Posted by n crowley

[QUOTE=Fday]Some people have brought it to my attention that I may have offended some of you when I posted: "most of you don't have a clue where cycling power and forces on the pedals are coming from".

And that in many cases is correct because as long as they can stomp on the pedals and use their PM, they don't care. If they did, pedalling would not have remained in its stagnant state over the past 50 years.

LOL Now that right there is funny. To scoff at the empirical measurment of force as the cause of "stagnation." My my my. Perhaps it the pedal in circle boys who are having trouble with the actual evidence that the measuring devices shows.

10-12.-2005, 08:48 PM

#190

n crowley

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Location: dublin ireland

Posts: 412

Re: pealling push up push down

Quote:

Originally Posted by jerryz

A powermeter can never generate pedal power or eliminate the injury and pain which the incorrect or unsuitable style of pedalling can cause. Perfecting the powermeter and not the pedalling is known as putting the cart before the horse.

11-12.-2005, 03:53 AM

#191

beerco

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Join Date: Nov 2003

Posts: 576

Re: pealling push up push down

Quote:

Originally Posted by Fday

If Coyle did not account for the mass differences of the thighs in the riders in his study (which he did not) he cannot say who is pushing harder and who is not.

Frank Day
PowerCranks

Um, here's a dumb experiment for you to try. Spin the cranks with the wheel off the ground. Now add 20lb weights to each pedal. Note how the weights cancel each other out, much to the chagrin of perpetual motion machines over the centuries.

I aspire to get into sales myself, but your methods are pathetic. No one likes a snake oil salesman.

11-12.-2005, 04:17 AM

#192

Fday

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Location: California

Posts: 669

Re: pealling push up push down

Quote:

Originally Posted by beerco

Oh my, where to start.

First, this has nothing to do with sales, it has to do with physics.

Addind 20 lbs to each pedal and spinning them will actually cause them to spin longer because there is more momentum and the bearing friction losses wil remain the same. Weight does not play a significant role here because the energy of the system remains constant and no work is done, so it requires no outside energy to maintain it. If it were not for frictional losses a spinning disk would spin forever.

That is not true for the thigh which moves in a back and forth pumping motion, constantly accelerating and decelerating. Since both thighs are accelerating and decelerating at the same time energy from one cannot be transfered to the other to keep it going. The total energy of this system is not constant so it constantly requires outside energy to keep it going. Further, we (or, at least, I am) are talking about how people have applied pedal force analysis. When you are "resting" and coasting what do you think the forces on the pedals are, Zero? Perhaps in space but not in the real world of cycling where legs have substantial mass and gravity is present. Trying to draw conclusions about what the muscles are doing from looking at pedal forces without taking into account the forces due to gravity is pretty much a complete waste of time.

11-12.-2005, 07:37 AM

#193

beerco

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Join Date: Nov 2003

Posts: 576

Re: pealling push up push down

Quote:

Originally Posted by Fday

Oh my, where to start.

That is not true for the thigh which moves in a back and forth pumping motion, constantly accelerating and decelerating.

Check again Barnum, the thigh moves up and down, not back and forth. For the thigh to move back and forth, the pelvis would have to move back and forth. It doesn't. What are your credentials anyway?

Even if it did though, that's not the point. The energy from the mass of the thighs (or mass of the lower leg) is balanced by the mass on the other side.

Losses from internal friction of the joints is another story entirely.

The main point is though that aerobic performance is not limited by muscle power, it's limited by oxygen consumption. This is borne out by the fact that single leg pedaling can elicit a VO2 of greater than 1/2 of VO2 max. Adding more muscles doesn't add anything to the mix. If anything, I would speculate that you'd have worse efficiency because of the losses in shuttling blood to more muscle groups...but then again, I'm an engineer, not an ex-phys.

11-12.-2005, 09:24 AM	#194
n crowley Registered User Join Date: Jul 2003 Location: dublin ireland Posts: 412	Re: pealling push up push down [QUOTE=beerco] Even if it did though, that's not the point. The energy from the mass of the thighs (or mass of the lower leg) is balanced by the mass on the other side. That's true but the clever rider knows how to undo this balance and get maximum advantage from the gravity effect of the downward leg. Adding more muscles doesn't add anything to the mix. If anything, I would speculate that you'd have worse efficiency because of the losses in shuttling blood to more muscle groups.. That depends on what muscles you are using, take rowers and skiers, if it did not add power they would not be using more muscles, but they do ?

11-12.-2005, 09:35 AM

#195

n crowley

Registered User

Join Date: Jul 2003

Location: dublin ireland

Posts: 412

Re: pealling push up push down

Quote:

Originally Posted by Fday

Fday, let's suppose that everything is possible in pedalling, how would you describe your Olympic Gold winning pedalling technique in the TT and Pursuit events.

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