Poor man's Powercranks? (PPC)

Discussion in 'Cycling Training' started by rmur17, Feb 16, 2007.

  1. Fday

    Fday New Member

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    Hey, one legged pedaling will make you better. I didn't say it wouldn't. It is just the potential for improvement is less. So, you pay your money (or don't pay your money) and you take your chances. Up to you.
     


  2. n crowley

    n crowley New Member

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    If all you are doing is zeroizing all negative forces, what does it matter whether the work involved is tangential or not.
     
  3. Fday

    Fday New Member

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    Because, for the same linear force one gets more torque if the direction of the applied force is tangential than if it is not. More torque means more power.

    The most extreme example of this principle would be when, with powercranks, you are standing on the cranks with your full weight on them with both of them at the bottom but not pedaling. The force on the cranks is maximum, being the full weight of the rider but the direction of the force is perpendicular to the pedaling circle so the torque is zero and no work is done even though the forces are high.

    It is a simple physical law, the more tangential the applied force is to the circle, the more effective is that force in generating work and power.
     
  4. n crowley

    n crowley New Member

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    I know about the tangential effect, but you are not applying any effective force or torque, all you are doing is unweighting to eliminate the negative force effect, or are you now claiming that you are producing effective pulling up force when using powercranks.
     
  5. Fday

    Fday New Member

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    The unweighting benefit is a completely separate benefit from the improved force application (more tangential) benefit. Yes, people are generating effective power on the backstroke but it is not from "pulling up" per se but mostly from the pulling back at the bottom and the pushing forward before the top. And, these forces are maximized by the unweighting, which cannot occur without "pulling up" the weight of the leg, even though there is no "pulling up" force on the pedals. At the 9 oclock position I suspect the forces are quite small on the pedals even though the cyclist is "pulling up" all of his leg weight so little actual work is being done there even though potential energy is being put into the leg, which is returned (in the form of work) on the downstroke.
     
  6. n crowley

    n crowley New Member

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    Wishful thinking ?
     
  7. Fday

    Fday New Member

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    HUH? What part was wishful thinking?

    Explain the improvements seen by joaco21 without incorporating such changes I mentioned. Give me a mechanism that explains how such such changes are possible in only one year. May I remind you increasing VO2max from about 72 to 85 ml/kg/min in one year and increasing FTP(1 hour) from 280 to 395 watts are not particularly easy improvements to achieve.

    He is either lying or they need to be explained as to how such improvements could occur.
     
  8. vadiver

    vadiver New Member

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    He changed his down stroke. He is begining to apply force much earlier than he was. He was only applying force at 9 o'clock before. Now he is applying it at either 1 or 2 o'clock I cannot remember.

    All of this is on the front side which your product does not provide any bennifit.

    By the way. What percentage of people show such grand improvements compared to the number of units you have in market place?
     
  9. Fday

    Fday New Member

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    Actually, we believe the PC's do provide down stroke improvements in the change of the tangential application of force on the downstroke. Otherwise it would not be possible to see such improvements. But, even if your explanation is correct, these improvements did not occur before, despite about 18 years of trying.

    And, even though most users do not have such good data as does this customer and most do not start at quite the same high level he was at, based upon the speed improvement reports we get, we think such improvements are pretty typical. So, the vast majority of new users will see substantially similar improvement after one year of exclusive use in training, more or less.
     
  10. vadiver

    vadiver New Member

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    Any crank will provide the improvement on the down stroke. In actuallity it is the rider that improves it not the crank. Unless your product changes the downstroke how is it different from a regular crank?

    18 years of waiting until the power stroke is 50% over is not the best cycling.


    What percentage. You talk about these speed improvement reports, what percentage of them compared to the nubmer of units you have shipped indicate such improvements?

    You always talk in vauge numbers. You have two studies that do not support your wild claims.

    Who cares what you think, what are the results in percentages. I think that if a rider were to wear pink shoes, they would win every grand tour and set the hour record in one year. That does not make it so. Your claims are all snake oil sales pitches.

    Another interesting study to do, I would not expect you to do it. Would be to see what effects your product have on a L/R leg imbalance. Does it improve it, make it worse, or have not effect.
     
  11. n crowley

    n crowley New Member

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    All you are doing in the upper and lower areas where you believe you are applying effective power is creating clearance for the inertia effect to run smoothly. I would agree with Vadiver, his extra power came from the forced extension of his downward power stroke which he could have extended by up to 60 degrees. The same explanation applies to Anquetil's mysterious high power production in time trials, he consciously extended his main power stroke by 60 degrees but in Anquetil's case it was more effective because he extended his to include the dead spot area.
     
  12. Piotr

    Piotr New Member

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  13. ric_stern/RST

    ric_stern/RST New Member

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  14. VeloFlash

    VeloFlash New Member

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    This is in reference to Dr Stephen Cheung.There was a Dr Stephen Cheung PhD who did a five month test of Powercranks on Pez Cycling News. Is this the same scientist?
     
  15. doctorSpoc

    doctorSpoc New Member

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    the article made me think...

    Joaco21 says he hasn't changed his training, but this is not true.. he's changed his training massively... he says he's gone from 20hrs a week... back in the day to 10hrs a week now. but this is after reaping the addapation over many, many years of hard training at much higher training volumes. and he says that he's not able to "recover" the way he used to... i wonder if this is basically what i observed this winter (a power meter really allows you to track exactly what you are doing and this was my 1st off season with a power meter). in the winter i was doing ~5hrs a week almost all thesh/SST... on a weekly volume of ~1/3 of what i was doing outdoors my 2x20 wattage went up on average ~20 watts from what i was typically doing outside. but i think the real reason for this was that evey time i stepped on the bike i was fresh... it didn't really mean i was more "fit". i'm sure if i had gone and done a 100+ km hilly road race or a stage race i would have been a dead man... but 10 - 20min at a time, high intensity efforts were no problem... in fact they were great? i'm not wholescale discounting the improvement due to changes in pedalling technique but i'm pretty sure at least some of the change in numbers might very well be due to his unrecognized, massive change in training volume... as well some of it might be also due to his use of a power meter and more effective training even at the lower volume that allows you to limit junk miles.. i've seen this in this my second season with a power meter... i'm doing the same TSS on 2/3 the volume of hrs.. so if you buy into TSS your training volume in hrs is not necessarily indicative of training stress.

    i guess my point really is that contrary to how it kinda looked at the onset this doesn't seem to be an example of where all the variables other than the use of power cranks have remained constant and so i would say that his improvement cannot be shown to be directly and completely attributable to the use of power cranks
     
  16. rmur17

    rmur17 New Member

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    yes it's the same person.
     
  17. vadiver

    vadiver New Member

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    The other thing this write up does not mention is how bad his peddaling technique was. As he stated here prior to his PC use he waited until 9 oclock to start applying force. After the use he starts applying force at 11 oclock. That is a big difference and could have been accomplished through proper coaching.

    A lot of changes were made.
     
  18. n crowley

    n crowley New Member

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    A bit confusing, he waited until 3 o'c, after PC's he started at 1 o'c. ? Pedaling technique is one part of cycling that coaches ignore, to them it is unimportant. Hop on your bike and stomp on the pedals, that's their teaching, ask Dr. Coggan.
     
  19. chainstay

    chainstay New Member

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    The Spanish rider also had this to say:

    I thought he was supposed to come back and share his racing results this past season. I just now read this hotly contested thread because a triathlete friend of mine was trying to pitch the PCs to me. Anecdotally, they seem to be a lot more popular investment for triathletes than road riders.
     
  20. swampy1970

    swampy1970 Well-Known Member

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    You make it sound so easy but the basic fact is that, unlike a car where you can set the ignition to fire before the crank reaches top dead center, it's a bit harder for a rider to quantify and act upon when training the following:

    a. where top-dead-center (ie 12 o'clock) is whilst sat on a bike as your head is well infront of the bottom bracket.
    b. when to start pushing - because of point (a)
    c. if the rider is not pedaling properly how does the coach know they're not pushing harder at 3 o'clock instead of somewhere just a few ticks after 12?
    d. if the rider knew exactly what his crank position was, could they "process" this information (if given by a handlebar computer if the PT or SRM units actually give out that info - i don't know I don't have one) such that they could simultaneously look at a display, ride their bikes without crashing and then somehow factor in how and when to start pushing whilst pedaling at 90+rpm?

    I assume that being "so learned" about the art of pedaling with the maximal application of torque on the cranks at any given time you're able to ride around at 28mph+ for extended periods, no?

    I find it hard (although I shouldn't) coming back to cycling after a considerable time off the bike to accept that way too many people are still dyed in the wool within the cycling comunity and are ready to hack anyone/anything to pieces without giving something a try. It's as bad as it was back in the 80's when it was almost hersey that someone,even with a 35" inside leg measurement, should ride something as large as 180mm cranks. Your knees would explode and you back would pretty much cease to function - well, that's what most would have you believe. I tried 165mm, 175mm and 185mm cranks and found the later faster. The ridicule was bording on silly...

    During my time away from the bike I dabbled in motorsports, and won regional SCCA trophies, but the difference was that if you didn't test then you were thought of as either lazy, neive or just not really that into it. Some settings worked on some cars that, well, just shouldn't have made an improvement - but they did - but you only find out from testing. Often times some changes only worked with particular driving styles for a given model of car.... There never was and never will be a "one fits all" approach that works.

    Now this is what I find really incredible - you have a product in Powercranks that's been around for a few years, had a few short term tests that look promising, an extended but not realy indepth scientific study but his results were rather good and a whole bunch of other folk who have posted good things about them.... but here's the kicker, what cycling product do you know of that gives you a 3 month guarentee? If the same "motorsports" mentality was observed in cycling then you'd get people trying things at the end of the season instead of "having a break"

    My 3 months is pretty much up - and they're still on my bike. I see results (bigger thighs, higher mph) and feel results. My pedaling has been drastically changed in a way that I'm not even going to describe but it makes me wonder what the f**k I was doing all those years when I did race. LOL They're still a pain in the arse cause I can't ride them for over 2 hours yet, nor can I ride them out of the saddle when I'm on the trainer... but FOR ME they work. Your mileage may vary...

    My personal opinion on them - they've given me the greatest short term improvement of any product apart from going from a road bike to a properly set up time trial bike and getting that took almost 3 months to test position, train in that position several times a week and then finally farm out the specs to a builder to get the frame - hardly a quick buy it and bolt it on deal. Now the only way that someone is going to take my basic adjustable powrcranks off me is if they pry them outa my cold dead hands.....
     
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