#11
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PowerCranks Study
wrote in message ... Phil Holman writes: This sounds more like a book promotion than a report on the cranks. Barkers at circus sideshows show more than this lead-on. How can you repeat such jive? By the way, remind me of the principal behind PC's. Are these the cranks that do not come around by themselves and require pulling up to make them remain synchronous (180 degrees apart)? Yes, that's correct Jobst. Reading between the lines of the newsletter, it looks like the study will reveal that training with the cranks will increase power output by 'x' amount. This might be a little more newsworthy than the umpteenth thread on shimmy but that's just my opinion. We'll just have to wait and see. There is no doubt that adding the effect of lifting (actually pulling back, lifting and pushing forward over the top will impart more power to cranks, however, it will not produce more power from the rider for a given aerobic level. We've gone over this before. The athletes who typically display the highest V02 max are those who utilize the most muscle mass (e.g. X-Country Skiers). Quite to the contrary. Engaging more muscles in propelling the bicycle burdens the heart and lungs with the overhead of more muscles rather than using the principal ones that are naturally used. If this were not so, foot plus hand cranks would produce a greater speed in TT's, flat and hill climbs, but they don't. It is my understanding that the lungs are not the constraint given their overcapacity in normal athletes. If they were, we would see venous blood desaturation in all athletes at and above their aerobic limit. The constraint is not just pumping capacity of the heart either. There is separation in performance between athletes with identical cardiac output. There are plenty of sports physiology references out there raining knowledge soup. Wearing one's soup bowl as a rain bonnet will do nothing but perpetuate an empty place holder for knowledge. As for hand and foot cranking, I've seen a number of these devices and it's probably the design constraints and unwieldy operation of such contraptions outweighing any power gains. I've also seen studies demonstrating the opposite for durations exceeding just anaerobic considerations. Anyone who has not trained with these cranks cannot ride with them, the requirement to keep positive forward torque on both cranks throughout rotation is difficult to accomplish. I'm sure that Lance Armstrong could not ride rollers with these at the bicycle show, something no bicycle racer I saw at InterBike 2002 do. If these cranks did what they claim to do, we wouldn't see riders dominate in races against PowerCrank devotees. I gained 1 mph in TT speed. This will not necessarily make one a winner of anything. The highest ranked cyclist using them is Paolo Bettini - UCI ranked 3rd in Jan 2003. Let's not overlook that with conventional cranks, the feet an legs are balanced and that it take no effort to rotate the cranks forward, clipped in and with non chain. With Power Cranks, this takes considerable effort, the feet not balancing each other. The limit of climbing hills or flat TT depends on aerobic capacity. That is what good bicycle racers have that others don't. I totally agree and the limiting factor in aerobic capacity is the ability of the muscles to utilize oxygen. The report should reveal what aerobic gains were made. Phil Holman |
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#12
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PowerCranks Study
"Tim McNamara" wrote in message ... In article , (n crowley) wrote: Rowers combine arm and leg power to improve performance and it does not burden their heart and lungs. Yes it does. Rowers are far less efficient aerobically than cyclists, and cannot keep up competitive efforts for an hour or more at a time, as can cyclists. It's very simple: more muscles in use increases the burden on the cardiovascular system. Quite true in the given context but if we were to wrap ourselves around the efficiency axle, we would all be pedaling around at 60 rpm. IMO there is nothing about improving efficiency with PC training. The expectation is that from the extra energy used in pulling up, some of it will manifest itself as useful work. The theory of constraints says that aerobic power output is not just limited by heart and lung capacity. Phil Holman |
#14
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PowerCranks Study
n crowley wrote:
No but I have an interesting pedaling technique which almost reverses the rowing technique, instead of the arms applying the power to the oars, the feet apply the power to the pedals while making maximum use of arm pulling up power to increase that pedal power whenever the necessity for this extra power arises. That just sounds like normal climbing techniques. Nothing that can be sustained over a longer period of time. -- Perre You have to be smarter than a robot to reply. |
#15
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PowerCranks Study
Originally posted by Per ElmsäTer n crowley wrote:
No but I have an interesting pedaling technique which almost reverses the rowing technique, instead of the arms applying the power to the oars, the feet apply the power to the pedals while making maximum use of arm pulling up power to increase that pedal power whenever the necessity for this extra power arises. That just sounds like normal climbing techniques. Nothing that can be sustained over a longer period of time. ============================================== Try using the normal climbing technique when riding a track pursuit at maximum power application and in an aerodynamic position. -- -------------------------- Posted via cyclingforums.com http://www.cyclingforums.com |
#16
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PowerCranks Study
n crowley wrote:
Originally posted by Per ElmsäTer n crowley wrote: No but I have an interesting pedaling technique which almost reverses the rowing technique, instead of the arms applying the power to the oars, the feet apply the power to the pedals while making maximum use of arm pulling up power to increase that pedal power whenever the necessity for this extra power arises. That just sounds like normal climbing techniques. Nothing that can be sustained over a longer period of time. ============================================== Try using the normal climbing technique when riding a track pursuit at maximum power application and in an aerodynamic position. Well that makes it more like a sprint position. Neither a sprint nor a track pursuit can be sustained over a longer period of time. So tell us instead how you accomplish this. -- Perre You have to be smarter than a robot to reply. |
#17
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PowerCranks Study
N? Crowley writes:
There is no doubt that adding the effect of lifting (actually pulling back, lifting and pushing forward over the top will impart more power to cranks, however, it will not produce more power from the rider for a given aerobic level. Quite to the contrary. Engaging more muscles in propelling the bicycle burdens the heart and lungs with the overhead of more muscles rather than using the principal ones that are naturally used. If this were not so, foot plus hand cranks would produce a greater speed in TT's, flat and hill climbs, but they don't. Rowers combine arm and leg power to improve performance and it does not burden their heart and lungs. I think you'll find that rowers row with their legs, their hands and arms functioning much like the foot and ankle of the bicyclist at the ends of a pedal strokes where inconsequential power is transmitted. If cyclists had the correct linear pedaling technique, they too could combine the pushing and pulling on fixed normal bars for additional pedal power without overloading their heart and lungs. The concept of linear pedal mechanisms and the like is a discredited belief of people who do not recognize reality. Bicycle riding has been scrutinized for more than a century and nothing new and useful has come up since the beginning of the chain driven bicycle. The most efficient pedaling is the technique that enables you to apply very effective power to the pedal from 11 to 5 'clock regardless of what your cadence is because this enables you to use a higher gear for the same effort of a rider who does not have this technique. The pulling up is done by the arm not the leg. I think you are mistaken. Go row a bit and observe what occurs. The bicyclist ha no lack of transmitting power but rather a limited aerobic capacity, and nothing will get past that. you seem to believe that power can be extracted from muscles without them demanding oxygen and glycogen. I think you ignore that the first measurement of interest by a bicycling team is lung capacity, not muscles or pedaling style. The explanation for the ineffectiveness of PowerCranks is that the pulling power of the leg is only effecive at a low cadence or when out of the saddle and even then can only be used for short periods. Not at all. The problem is that lifting the leg against gravity is work even without adding any torque. On normal cranks the legs are balanced and require no effort to go around, up or down. Let's not overlook that with conventional cranks, the feet an legs are balanced and that it take no effort to rotate the cranks forward, clipped in and with non chain. With Power Cranks, this takes considerable effort, the feet not balancing each other. If you were pedaling for most benefit, the feet would not be balanced as you should be unweighting the idling pedal as soon as you stop applying the power, making the most out of the assistance of gravity. In that one instance PowerCranks could prove to you the error of your ways. Why "should" I be unweighting the "idling" pedal? That makes unnecessary work that I can do without. This work is better done with the descending leg. Invoking other muscles to do this is inefficient. That the downward pushing muscles have the ability to do this is amply demonstrated and that there is reserve is demonstrated in sprints that use up the aerobic capacity. You are suggesting that there is an inefficiency in the principal muscles we use to propel ourselves and engaging other unnatural muscles improves power generation. I don't believe a word of it. The limit of climbing hills or flat TT depends on aerobic capacity. That is what good bicycle racers have that others don't. True but knowing how to get the most out of your pedals and cranks can help you to make the most of your aerobic capacity. You think you can fool the muscles into doing free work. Jobst Brandt |
#18
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PowerCranks Study
Pete Cresswell writes:
Engaging more muscles in propelling the bicycle burdens the heart and lungs with the overhead of more muscles rather than using the principal ones that are naturally used. Does that supply me with a rationale to not learn how to spin? You don't need to do anything but push down on pedals to spin. Fortunately, rigidly connected cranks constrain the feet to move in circles and do so in a balanced manner. All the ride needs to do is inject some energy into that rotation at a suitable rate. Let's not get pedaling rate confused with "round pedaling", a subject similar to the study of ankling of the past. Jobst Brandt |
#19
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PowerCranks Study
N? Crowley writes:
No but I have an interesting pedaling technique which almost reverses the rowing technique, instead of the arms applying the power to the oars, the feet apply the power to the pedals while making maximum use of arm pulling up power to increase that pedal power whenever the necessity for this extra power arises. That's interesting. Well trained bicycle racers do not pull up on the bars at all. The bars are used in sprinting or steep climbing while standing in order to counter the torque of pulling up on the rear pedal. This is done by pushing down with one hand and pulling up with the other, the push being grater than the pull. If this were not down the rider would fall off the bicycle. This is not work because the arms do not articulate while providing this counter force. However, for the longer term, a gear is selected that does not require pulling up on pedals. That's the reason for gears. I think you should ride some more and observe what occurs. Jobst Brandt |
#20
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PowerCranks Study
On Sat, 04 Oct 2003 06:57:45 GMT, "Phil Holman"
may have said: Reading between the lines of the newsletter, it looks like the study will reveal that training with the cranks will increase power output by 'x' amount. Any bets that the gadget merely achieves what can be had by a clipless-pedal user (or toeclip user, for that matter) with proper training *without* the freewheeling crank and its attendant disadvantages? I have little doubt that high-level professional racers already employ the technique that this gadget's makers claim can only be learned through the use of their device. They seem to think there's magic in their alleged "positive feedback", but what I see is *negative* feedback for a non-pull return stroke, and I'm sure there are ways to learn to pull without their widgetry. -- My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I don't respond to something, it's also possible that I'm busy. |
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