pealling push up push down

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Most look at the pedaling forces measured in cyclists and assume that these forces are due entirely to muscle contractions, and from this conclude that all power comes from pushing and none from pulling. I don't believe I have ever seen an analysis in any scholarly journal (or anywhere else for that matter) that mentions gravity playing any role in the development of these forces... Probably because assumptions are made that it doesn't play that much a significant role in pedaling forces.


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Probably because assumptions are made that it doesn't play that much a significant role in pedaling forces.


:)

That's what I was going to say to his next reply! The key word in his last post was scholarly. Something his arguments don't seem to be.

So how much power does gravity contribute?

Gravity contributes nothing to the power generated. Gravity only complicates trying to figure out what the muscles are actually doing by looking at the forces on the pedals. You would generate the same amount of power as you do now if you were pedaling in space but the measured pedal forces would be different.

Probably because assumptions are made that it doesn't play that much a significant role in pedaling forces.


:)

It could be as simple as no one has thought about it. Most scholarly research should include what assumptions are being made in evaluating the data. It is not valid to assume they are assuming such without such a statement in the paper. Whatever the reason this confounding factor has been ignored in the literature. Even if such an assumption is being made, assuming the world is the center of the universe or is flat or any other assumption doesn't make it so.

Rowers and skiers don't add a lot of power with their arms. If you look at HPV projects, they almost all started out with legs and arms powering the machine (helicopter, cycle airplane etc.). After testing and consultation with the ex-phys crowd, they all switch to legs only. Why do you suppose that is?





Independent use of arms and legs in cycling is not very successful as it has the same effect as trying to push and pull with the legs. But when arms and legs are combined and work as a unit results are very different and power is increased. HPV riders are not in a suitable position nor do they have the style of pedalling that's required for combined arm/leg pedalling. In addition they cannot use the gravity effect and that forms part of it.

But when arms and legs are combined and work as a unit results are very different and power is increased... Canada's head coach of the national team, with whom I happened to have done my level 2 in road cycling, also advocates the use of arms, especially while riding TT using aerobars. A bit like (but not as much) when we climb a hill.


Gravity contributes nothing to the power generated. Gravity only complicates trying to figure out what the muscles are actually doing by looking at the forces on the pedals. I agree. This is a complicated issue.

I am trying to think of a endurance sport, in which there is no recovery. I can't find one. In most sports, there is a recovery phase, that allow :
1 - a short rest
2 - to position the limb for an other stroke
3 - to let the other limb do its job in the most efficient way

In swimming the free style, the recoverying arm must exit the water. It will carry its own weight. Running, skating, rowing...

Makes sense that there is a recovery phase in cycling as well. Like in the other sports, the recoverying limb also carry its own weight.

:)

[QUOTE=SolarEnergy]Canada's head coach of the national team, with whom I happened to have done my level 2 in road cycling, also advocates the use of arms, especially while riding TT using aerobars. A bit like (but not as much) when we climb a hill.





Only when the leg power application and arm resistance lines are parallel can most effective use be made of the arms. This cannot happen with aerobars or with the natural pedalling style. You need "Scott Rake" type bars and a very different pedalling style.

If one doesn't account for gravity one cannot know what role the muscles are playing in causing those resultant forces.

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All you have to do is zero the strain gauges with feet on the pedals with muscles relaxed...real tough. I haven't read the Coyle article recently, but to get meanigful power readings you have to have the system read zero under no power conditions, thereby taking into acount any forces due to gravity....sheeesh.



Second, the losses I referred to in the pedaling motion have nothing to do with internal friction losses, they are present even if one assumes no internal friction. They come about because of the constant accelerations and decelerations of the legs, mostly the thigh, that require outside energy to maintain since the total energy of the system is constantly changing and there is no way to store and retrieve this energy (if there were the total energy of the system would not be changing). Do the analysis. It is fairly simple to do, albeit quite tedious. I have done it and I know what is going on.

I understand what you're talking about here, but what does this have to do with the claims for your device? The energy to move the thighs still has to be provided by the rider. Why is it better to have a puny hip flexor do it when you've got a big quad down there? Why is it better to use small muscles instead of big? Why is it more efficient to shuttle blood to more muscle than less?

All you have to do is zero the strain gauges with feet on the pedals with muscles relaxed...real tough. I haven't read the Coyle article recently, but to get meanigful power readings you have to have the system read zero under no power conditions, thereby taking into acount any forces due to gravity....sheeesh.

If it is so easy why don't these researchers "zero the strain gauges with feet on the pedals with muscles relaxed" as you propose? At least you seem to be coming to the conclusion this should be done. Now, you should be asking why don't researchers do so




I understand what you're talking about here, but what does this have to do with the claims for your device? The energy to move the thighs still has to be provided by the rider. Why is it better to have a puny hip flexor do it when you've got a big quad down there? Why is it better to use small muscles instead of big? Why is it more efficient to shuttle blood to more muscle than less?

This (the energy cost of pedaling) has pretty much nothing to do with the claims for my device except as a way of partially explaining the results we see and PC'ers typically lower their cadence. I also bring it up because those who argue against my device frequently say pedaling has no energy cost. They are wrong. BTW, the HF's are not that puny unless you are looking at the aerobic capacity of these muscles, which is generally puny.

Regarding your other questions you are doing a lot of rationalizing to explain your bias. You should instead be asking instead "what does the data show? If the data shows that the use of PC's does improve efficiency (as shown Luttrell for instance) or power (as reported by many anecdotal reports) then you should be asking why is this happenning, rather than arguing that the data cannot be correct. If the data is insufficient as to what PC's do then you should be arguing for more data rather than arguing what you think PC's can or cannot do based on no experience with them and admittedly inadequate data. Theory should change to agree with the current data rather than expecting the data to change to agree with the current theory.

If it is so easy why don't these researchers "zero the strain gauges with feet on the pedals with muscles relaxed" as you propose? At least you seem to be coming to the conclusion this should be done. Now, you should be asking why don't researchers do so.

You misunderstand. If they didn't zero the instruments, the data wouldn't work out at all. Ergo, Coyle must have zeroed his pedals.



Regarding your other questions you are doing a lot of rationalizing to explain your bias. You should instead be asking instead "what does the data show? If the data shows that the use of PC's does improve efficiency (as shown Luttrell for instance) or power (as reported by many anecdotal reports) .

I haven't read the full studies you did, but people smarter than I have and they suggest that the studies were done with improper control groups which would all but guarantee an improvement only in the target group.

When real studies are done, one starts with a hypothesis for a mechanism. Then they either prove or disprove their hypothesis, sometimes even disproving their hypothesis is a good thing because it leads to new stuff.

You on the other hand started out with a product. It now sounds as if you had no hypothesis when you invented it. Then you made a study with no hypothesis fishing for what it does. Maybe you found something, maybe not because you still propose no mechanism for the improvement.

In other words, snake oil.

I know that your full time job is to push your powercranks, but unfortunately my full time job is not to debunk snake oil salesmen so I hereby plonk this discussion.

You misunderstand. If they didn't zero the instruments, the data wouldn't work out at all. Ergo, Coyle must have zeroed his pedals.

Maybe someone who was there would tell us how he did zero his pedals since he didn't tell us how he did so (or, more importantly from a study perspective, even that he did) in the study. Unless any of these respected researchers tells us they did so my presumption is they did not. It is pretty bold (or foolish) of you to presume these people did.

I haven't read the full studies you did, but people smarter than I have and they suggest that the studies were done with improper control groups which would all but guarantee an improvement only in the target group.

Perhaps you should critically read those studies before you accept the pronouncements of "those smarter" than you. Then you might let me know what was so improper about these control groups, or the studies themselves. You might be surprised where you fall on the smartness scale, or then again, maybe not.

[QUOTE=Fday]Maybe someone who was there would tell us how he did zero his pedals since he didn't tell us how he did so (or, more importantly from a study perspective, even that he did) in the study. Unless any of these respected researchers tells us they did so my presumption is they did not. It is pretty bold (or foolish) of you to presume these people did.





Frank, if a circular and a stomper rider unweighted their pedals, who would be fastest in a 4K pursuit, both riders of equal fitness etc.

[QUOTE=Fday]Maybe someone who was there would tell us how he did zero his pedals since he didn't tell us how he did so (or, more importantly from a study perspective, even that he did) in the study. Unless any of these respected researchers tells us they did so my presumption is they did not. It is pretty bold (or foolish) of you to presume these people did.





Frank, if a circular and a stomper rider unweighted their pedals, who would be fastest in a 4K pursuit, both riders of equal fitness etc.

The one with the best combination of power and aerodynamics I would presume. If they were equal in both these respects I would put my money on the one with the smoothest power application, i.e., the "circular" pedaler.

The one with the best combination of power and aerodynamics I would presume. If they were equal in both these respects I would put my money on the one with the smoothest power application, i.e., the "circular" pedaler.



Why ? Don't forget the movement of the upper leg is now ruled out of the equation.

The one with the best combination of power and aerodynamics I would presume. If they were equal in both these respects I would put my money on the one with the smoothest power application, i.e., the "circular" pedaler.



Why ? Don't forget the movement of the rising leg is now ruled out of the equation.

Why ? Don't forget the movement of the rising leg is now ruled out of the equation.

Because there is an introduced inefficiency in the small but frequent speed changes that comes from the mashing style vs the smoother power application. So, for the same average power there will be a subtle difference in average speed. This inefficiency is similar to why one will get better gas mileage when using cruise control over trying to maintain "constant" speed manually.

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). Frank Day
PowerCranks

Frank, in terms that cyclists might understand (e.g., category 1, 2, 3, etc.) or physiological terms (e.g., VO2max of 65 mL/kg/min, MAP of 380 W) could you explain who your typical user is that "...will gain 40% in power, at least for reasonable distances (40K or so), after 6 to 9 months of exclusive use..."

Thanks
Ric

Because there is an introduced inefficiency in the small but frequent speed changes that comes from the mashing style vs the smoother power application. So, for the same average power there will be a subtle difference in average speed. This inefficiency is similar to why one will get better gas mileage when using cruise control over trying to maintain "constant" speed manually.




I would put my life savings on the stomper. How could your circular power application be smooth when you are applying almost nil in the dead spot area and maximum in the 3 o'c area. What the circular style does is extend the effect of both the upper and lower dead spot areas, while you are busy rolling one foot over the 12 o'c area and scraping the mud off your shoe in the 6 o'c area, the stomper is able to avail of an earlier start to his downstroke and a follow through at the end.

Frank, in terms that cyclists might understand (e.g., category 1, 2, 3, etc.) or physiological terms (e.g., VO2max of 65 mL/kg/min, MAP of 380 W) could you explain who your typical user is that "...will gain 40% in power, at least for reasonable distances (40K or so), after 6 to 9 months of exclusive use..."

Thanks
Ric

First, understand that a 40% increase in power is only a 2-3 mph speed increase for almost everyone. So, we are not talking about unobtainable speeds.

Our "typical" user who can expect to gain that much is almost every triathlete except the very elite and most cyclists from Cat 2 or 3 down. One experienced triathlete reported improving his usual 12 mile "testing" loop time trial speed from 20 to 25 mph in 6 months and he has subsequently, after 3 years, improved to 28 mph. This is almost a doubling of power in only 6 months. The more elite cyclists and triathletes are more typically seeing about 25% improvement (for instance Phil Holman, a masters track cyclist improved his top speed from 35-38 mph and pursuit speed from 30 to 32 mph in 7 months of almost exclusive use, which calculate to be about 28% improvement, if I remember correctly).

So, while there seems to be quite a bit of variation amongst users a very large proportion of those who take them seriously and use them a lot seem to see about 2-3 mph improvement in that time frame. Some see less, some see more.

I would put my life savings on the stomper. How could your circular power application be smooth when you are applying almost nil in the dead spot area and maximum in the 3 o'c area. What the circular style does is extend the effect of both the upper and lower dead spot areas, while you are busy rolling one foot over the 12 o'c area and scraping the mud off your shoe in the 6 o'c area, the stomper is able to avail of an earlier start to his downstroke and a follow through at the end.

Why do you presume the circular pedaler is applying "almost nil" at the dead spot area. One of the major areas of improvement found in PowerCrankers is at the top and bottom of the stroke. Circular pedaling is more than just unweighting.

Look, you can put as much money as you like on the stomper if you wish. However, you will be betting against the physics and will most surely lose every time.

If the average power is the same but the stomper has more power variation in the stroke the maximum and minimum speed of this rider will be more than the rider with a more even (or perfectly even stroke where there would be no speed variation) stroke. Unfortunately, because wind resistance varies with the square of the speed, the average wind resistance will be greater for the stomper than for the even pedaler which means, he either has to put out more power to ride at the same average speed or must slow down to ride at the same power. The greater the power variation the greater the losses.