#11
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Powercranks
Hjalmar Duklęt wrote:
Well, this is probably true for maximum effort but I would believe that using extra muscle groups to do the work would be benefitial when it comes to endurance and submaximal efforts. It would take longer before the mucles were exhausted. If you cycle regularly muscles do not become exhausted provided you keep them fuelled. You may be stiff the next day but that is another matter. -- David Damerell Kill the tomato! |
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#12
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Powercranks
Hjalmar DuklęT wrote:
wrote in message news:NdmTb.12155- $XF6. - nic.net... Bill who? writes: Hi. I'm new the the group but thought this would be the right place to ask. Just got a set of Powercranks and put them on the bike I've been using on my Computrainer. Gee, I used to enjoy my Computrainer! Now I can only ride it for about 3 miles! Anyone else had experience with Powercranks? Does this get better or is this why I see them on e-bay so often? Here is some interesting feedback: http://www.pezcyclingnews.com/?pg=fu...//www.pezcycl- ingnews.com/?pg=fullstory&id=1882 The author, Josh Horowitz, should be comming upon his one month update shortly. That makes painful reading for me, having ridden Power Cranks on a demo just long enough to understand what the concept is. No doubt it is exhausting and it builds new muscles to do a task that ordinary cranks make unnecessary. The easiest way to return the foot/pedal/leg from the bottom of the stroke to the next power stroke is to let it ride. That is, unless you don;t have two reasonably equal legs that are balanced when you sit on the bicycle without a chain. If you see two riders, one with weight lifter muscles and a slim, no fat rider with big lungs, I believe that most riders will recognize the bikie as the slender guy. That's because only for sprints are big extra muscles useful. The limit of most fit bicyclists is not muscles but cardiovascular. More muscles and using otherwise unused muscles in propulsion is someone's dream of a speed secret. This goes in the same bucket as round pedaling and ankling. This sounds so much like patent medicine with no supporting evidence: http://www.powercranks.com/http://www.powercranks.com/ Jobst Brandt Well, this is probably true for maximum effort but I would believe that using extra muscle groups to do the work would be benefitial when it comes to endurance and submaximal efforts. It would take longer before the mucles were exhausted. During a 5 hours road race I guess this is what counts, not your cardiovascular maximum limit.Or am I completely wrong here? Hjalmar I have been using them for about 8 weeks now and training 3 sessions week for about an hour on them. I can now ride up to 3 hours without real problem but at lower cadences than I would normally be at. I ca detect an improvement in my riding in terms of strength (no I canno back this up except that my best race results have fallen in this time) No doubt Ric Stern will tell you that it has not been shown that rounder stroke is necessarily better, but I believe that it could b more efficient to spread the work load among different muscles It certainly gets easier fairly quickly so worth persevering Pete - |
#13
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Powercranks
"Hjalmar Duklęt" writes:
wrote in message ... If you see two riders, one with weight lifter muscles and a slim, no fat rider with big lungs, I believe that most riders will recognize the bikie as the slender guy. That's because only for sprints are big extra muscles useful. The limit of most fit bicyclists is not muscles but cardiovascular. More muscles and using otherwise unused muscles in propulsion is someone's dream of a speed secret. Well, this is probably true for maximum effort but I would believe that using extra muscle groups to do the work would be benefitial when it comes to endurance and submaximal efforts. It would take longer before the mucles were exhausted. During a 5 hours road race I guess this is what counts, not your cardiovascular maximum limit.Or am I completely wrong here? For long events, the limits are very much cardiovascular. Weight is weight, whether it's fat, muscle or bike, and it takes more work to haul weight uphill. In any sort of race with any significant climbing, the lighter rider is at an advantage and it doesn't matter if it's fat or muscle. When I was doing randonees this summer, I noticed that the scrawny un-muscular guys tended to be the fastest over 200, 300, 400, 600 and 1200 kilometers. At 6'3" (sheesh, I shrank an inch over the last 10 years) and 210 lbs, I found that I was at a bit of a disadvantage over the long haul. Look at the 1996 Tour winner, Bjarne Riis. He had skeletal legs, practically no muscle at all and practically no body fat (IIRC he was at about 4% body fat). My thighs are bigger than Armstrong's and I suspect I can lift more weight in a squat, but he's able to climb l'Alpe-d'Huez literally twice as fast as I can. He weighs 60 lbs less and has cardiovascular capacity and a VO2 max I can only dream about. On the flat, where wind resistance is the primary issue, the larger more muscular rider tends to have an advantage. Compare the TT prowess of Miguel Indurain and Marco Pantani for an example. |
#14
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Powercranks
Tim McNamara wrote:
On the flat, where wind resistance is the primary issue, the larger more muscular rider tends to have an advantage. Compare the TT prowess of Miguel Indurain and Marco Pantani for an example. Even in a flat TT comparison, it's not Indurain's muscle mass that makes him faster than Pantani. Indurain simply has a bigger cardiovascular engine. Pantani's power-to-weight ratio is higher, even though his max. power output is lower. -- terry morse Palo Alto, CA http://www.terrymorse.com/bike/ |
#15
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Powercranks
finally a scientific response.
-- -------------------------- Andre Charlebois BPE, MCSE4.0, CNA, A+ webmaster for Triathlon New Brunswick www.TriNB.com "Carl Fogel" wrote in message om... "Bill" wrote in message ... wrote in message ... Hi. I'm new the the group but thought this would be the right place to ask. Just got a set of Powercranks and put them on the bike I've been using on my Computrainer. Gee, I used to enjoy my Computrainer! Now I can only ride it for about 3 miles! Anyone else had experience with Powercranks? Does this get better or is this why I see them on e-bay so often? Thanks in advance! JohnT. Here is some interesting feedback: http://www.pezcyclingnews.com/?pg=fullstory&id=1882 The author, Josh Horowitz, should be comming upon his one month update shortly. Bill Dear John and Bill, In the article that Bill mentions, the rider makes the same complaint as John--using the Powercranks leaves him sore as hell and feels quite awkward, at least at first. He couldn't ride very long with them for more than a week. If he's sore because he's using different muscles, then he may get used to it. But if cardiovascular capacity is what really matters in bicycling for hours, then using more or different muscles is unlikely to help him rider faster. If there were any mechanical advantage, then it would show up immediately. If it trains him to change the way that he pedals in some more efficient way, then he should be able to return to a normal crank, pedal in his new style, and achieve the same results. (Or better, since a normal crank of the same strength is lighter.) If it's a Hawthorne-style placebo effect (initial improvement caused by being observed), then it will join many other contraptions that motivated people to work harder and then credit the contraptions with the results of their extra effort. Carl Fogel |
#16
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Powercranks
Carl Fogel wrote:
If it trains him to change the way that he pedals in some more efficient way, then he should be able to return to a normal crank, pedal in his new style, and achieve the same results. (Or better, since a normal crank of the same strength is lighter.) Powercranks are intended to as a training device, not as a permanent replacement for conventional cranks. The idea is exactly as you say: to change the way that someone pedals so that when he returns to normal cranks he will achieve better results. It's sort of like those ankle weights that basketball players use in practice -- they don't wear them in the actual game. I do not know if the results match the theory. |
#17
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Powercranks
Terry Morse wrote:
Tim McNamara wrote: On the flat, where wind resistance is the primary issue, the larger more muscular rider tends to have an advantage. Compare the TT prowess of Miguel Indurain and Marco Pantani for an example. Even in a flat TT comparison, it's not Indurain's muscle mass that makes him faster than Pantani. Indurain simply has a bigger cardiovascular engine. Pantani's power-to-weight ratio is higher, even though his max. power output is lower. Even though Indurain had lower power-to-weight than Pantani, across individuals CdA scales less than linearly with mass -- in the ballpark of perhaps the cube root or so. Besides, Pantani's ears stuck out. |
#18
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Powercranks
The verdict of the experts is in: sub-sprint-intensity cycling
performance is completely determined by cardiovascular capacity and wind resistance, with weight also playing a role only on steep climbs. Having thought this through to its logical conclusion, I hereby offer three suggestions that I believe will revolutionize cycling as we know it: 1. Lower your seat and handlebars by six inches; you'll probably have to purchase a smaller frame, but it will be worth it. Sitting high enough to straighten the legs to within 30 degrees or so of full extension is a waste. People do it in the name of "efficiency" or "muscular endurance" or some such pseudo-science, but obviously if you sit six inches lower you'll still have the same cardiovascular capacity, hence the same power. Your wind resistance will be considerably less due to your lower profile, so you'll go faster. 2. The appropriate innovation in cranks is not PowerCranks but ShortCranks -- the shorter the better, but something in the neighborhood of 60 mm should suffice. Any machine shop should be able to make this modification to your existing cranks, as long as they're not carbon. This will further stabilize and reduce your aerodynamic profile, and again your cardiovascular system will produce as many watts as ever. The result, of course, is that you'll go faster still. As an additional benefit, bicycles fitted with ShortCranks can have lower bottom brackets, allowing you to sit closer to the ground and achieve even less wind resistance; frame builders, however, will need some time to catch up to this innovation. 3. Get rid of all those unnecessary gears. You've got just as much cardiovascular capacity pedaling at 30 rpm or 150 rpm as you do in the so-called "recommended range" of 90 to 110 rpm, so one gear is all anyone needs. Because of all the wind resistance saved by the preceding recommendations, you'll be going much faster than usual, so you should choose the largest possible combination (53x11, or higher if you can find the components) for your one gear. The combination of reduced weight and improved aerodynamics (the latter cannot be ignored even at climbing speeds) will have you ascending faster than ever! Abandon those old wives' tales about "strength" and go climb your local benchmark - be it Page Mill, Mt. Washington, or Mont Ventoux - in a 53x11, with 60 mm cranks, sitting six inches lower than you're sitting today. It'll be like nothing you've known before. |
#19
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Powercranks
Terry Morse writes:
Tim McNamara wrote: On the flat, where wind resistance is the primary issue, the larger more muscular rider tends to have an advantage. Compare the TT prowess of Miguel Indurain and Marco Pantani for an example. Even in a flat TT comparison, it's not Indurain's muscle mass that makes him faster than Pantani. Indurain simply has a bigger cardiovascular engine. Pantani's power-to-weight ratio is higher, even though his max. power output is lower. You also have to factor in aerodynamics; the two are not going to be that much different but Indurain has more power available by having much more muscle mass. So while Pantani's power-to-weight ratio is better, Indurain's "power-to-drag" ratio is superior. The math has been published on this, jeez, years ago. |
#20
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Powercranks
"Andre" writes:
finally a scientific response. Carl Fogel: If it's a Hawthorne-style placebo effect (initial improvement caused by being observed), then it will join many other contraptions that motivated people to work harder and then credit the contraptions with the results of their extra effort. The Hawthorne effect is an interesting notion in this regard, although it's not a placebo effect per se. There are similarities in the two concepts that make them easy to confuse. Here's some information on the Hawthorne effect for the bored: http://www.psy.gla.ac.uk/~steve/hawth.html |
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