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#31
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Beware of PowerCranks
"Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: wrote in message ups.com... On Jun 3, 5:46 am, wrote: On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman" Frank Day. His last posts here were after a scientific study showed a statistically significant 1.5% gross efficiency improvement. The experts here still wouldn't buy it. No offense, but that sounds like 200 watts rising to 203 watts. Well, the difference was in gross efficiency, not in power. Frank Day calls them PowerCranks, not EfficiencyCranks. Phil may know whether there has been a published RCT that shows an increase in power. I just checked their website and found another study of trained cyclists that showed a 15.6% increase in VO2max and an 11.6% icrease in max power. My understanding- which may not be correct- is that VO2 max is biologically determined and that training does not significantly change this. I'll assume you are talking about a theoretical ceiling and not the difference in the same athlete being in shape and not in shape. The theoretical ceiling is biologically determined but what biologically constitutes that ceiling is still up for discussion. As I understand it (it's been a while since I had any reason to look into this stuff and maybe new data has come to light in the interim), if your VO max is 60 ml/kg/min then that is basically it. You can't "train up" your VO2 by 15.6% at least from the data I had looked at a few years back. I'll resist the urge to challenge your understanding on the basis of a rider who loses 5 kg of body weight. When dealing with PCs, we are not interested in that aspect of any VO2Max improvement. Miguel Indurain's published VO2 max was 88 ml/kg/min which is very much at the high end. Lemond's was reported to be over 90 ml/kg/min. A training technique that would net guys think this a 15.6% increase would make them invincible. Nobody could touch them in an event like the Tour de France. You can't get even those kinds of gains by doping. You're not going to see those kind of gains in athletes who have maximized their training potential. In any event, VO2Max is a poor predictor of race performance within a strata of racing abilities. From the test, it is not clear whether actual 02 uptake was measured or if VO2Max was estimated from the time to exhaustion in the incremental test. There are things you can train up by quite a bit, such as your sustained power output at lactate threshold, Wingate test, etc. Those things are important and can make a big difference in race results. Yep. Ive alluded to the fact that an appropriate test needs to be done with these things. I.e. measure what is directly attributable to racing performance. PowerCranks have always been marketed a bit too much like the Second Coming for my tastes. I thought you of all people could separate the science from the emotion. Hype annoys me, what can I say. When the hype seems mighty unrealistic, I get suspicious of there being a dose of snake oil in the mix. IMHO people who are extremely competitive have a tendency to be a bit gullible when it comes to things that promise improved performance. Of interest to me would be whether whatever benefits are gained from PowerCranks are durable. When people go back to regular cranks for racing, do the maintain the neuromuscular pattern that a PowerCrank is supposed to develop? Or do they go back to normal riding quickly? Do they have to "brush up" with the PowerCranks periodically? My hunch is that the muscle recruitment pattern is quickly unlearned and the rider goes back to a normal pedal stroke within a week or so after returning to using normal cranks. From my experience, it's subject to the same reversible process as regular training. How much fitness do you think you'll lose in a week? I haven't pedaled a PC in about 3 years but I can still employ the technique for sustained periods because I still maintain the riding technique with regular cranks. Phil H |
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#32
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Beware of PowerCranks
In article ,
"Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: wrote in message ups.com... On Jun 3, 5:46 am, wrote: On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman" Frank Day. His last posts here were after a scientific study showed a statistically significant 1.5% gross efficiency improvement. The experts here still wouldn't buy it. No offense, but that sounds like 200 watts rising to 203 watts. Well, the difference was in gross efficiency, not in power. Frank Day calls them PowerCranks, not EfficiencyCranks. Phil may know whether there has been a published RCT that shows an increase in power. I just checked their website and found another study of trained cyclists that showed a 15.6% increase in VO2max and an 11.6% icrease in max power. My understanding- which may not be correct- is that VO2 max is biologically determined and that training does not significantly change this. I'll assume you are talking about a theoretical ceiling and not the difference in the same athlete being in shape and not in shape. The theoretical ceiling is biologically determined but what biologically constitutes that ceiling is still up for discussion. As I understand it (it's been a while since I had any reason to look into this stuff and maybe new data has come to light in the interim), if your VO max is 60 ml/kg/min then that is basically it. You can't "train up" your VO2 by 15.6% at least from the data I had looked at a few years back. I'll resist the urge to challenge your understanding on the basis of a rider who loses 5 kg of body weight. When dealing with PCs, we are not interested in that aspect of any VO2Max improvement. That's good, because of course PowerCranks would have no different effect on this than any other cranks. That's simply a matter of weight loss. Miguel Indurain's published VO2 max was 88 ml/kg/min which is very much at the high end. Lemond's was reported to be over 90 ml/kg/min. A training technique that would net guys think this a 15.6% increase would make them invincible. Nobody could touch them in an event like the Tour de France. You can't get even those kinds of gains by doping. You're not going to see those kind of gains in athletes who have maximized their training potential. In any event, VO2Max is a poor predictor of race performance within a strata of racing abilities. From the test, it is not clear whether actual 02 uptake was measured or if VO2Max was estimated from the time to exhaustion in the incremental test. VO2 is not the sole determinant of athletic performance- if it was, all we'd have to do is measure VO2 max and we'd know the winner. However, given that the literature used to indicate that VO2 was basically genetically determined- whether that is still the case I don't know- it seems highly unlikely that one can train up one's VO2 by 15.6%. There are things you can train up by quite a bit, such as your sustained power output at lactate threshold, Wingate test, etc. Those things are important and can make a big difference in race results. Yep. Ive alluded to the fact that an appropriate test needs to be done with these things. I.e. measure what is directly attributable to racing performance. PowerCranks have always been marketed a bit too much like the Second Coming for my tastes. I thought you of all people could separate the science from the emotion. Hype annoys me, what can I say. When the hype seems mighty unrealistic, I get suspicious of there being a dose of snake oil in the mix. IMHO people who are extremely competitive have a tendency to be a bit gullible when it comes to things that promise improved performance. Of interest to me would be whether whatever benefits are gained from PowerCranks are durable. When people go back to regular cranks for racing, do the maintain the neuromuscular pattern that a PowerCrank is supposed to develop? Or do they go back to normal riding quickly? Do they have to "brush up" with the PowerCranks periodically? My hunch is that the muscle recruitment pattern is quickly unlearned and the rider goes back to a normal pedal stroke within a week or so after returning to using normal cranks. From my experience, it's subject to the same reversible process as regular training. How much fitness do you think you'll lose in a week? I haven't pedaled a PC in about 3 years but I can still employ the technique for sustained periods because I still maintain the riding technique with regular cranks. The purported unique benefit of PowerCranks is as much neurological as muscular. The rider has to develop a different pattern of muscle recruitment and develop new "muscle memory." That pattern of muscle recruitment is not necessary on regular cranks, and I suspect that the new pattern would be lost quickly- perhaps in a couple of rides. |
#33
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Beware of PowerCranks
On Sun, 03 Jun 2007 19:26:41 -0500, Tim McNamara
wrote: However, given that the literature used to indicate that VO2 was basically genetically determined- whether that is still the case I don't know- it seems highly unlikely that one can train up one's VO2 by 15.6%. An untrained person can, with training, increase VO2max that much. But once someone has been training seriously for some time they can't. -- JT **************************** Remove "remove" to reply Visit http://www.jt10000.com **************************** |
#34
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Beware of PowerCranks
Ride Faster wrote:
I had the same experience with PowerCranks. This product is garbage. " wrote: It's really outrageous for them Powercrank to charge so much for a faulty design. "Tim McNamara" wrote The proprietor of PowerCranks used to post here to rebut criticisms, but I haven't seen anything from him for a while. Basically I suspect that the price is high because (1) he promises that his product will make you faster for which competitive people will pay lots of money and (2) his business is small enough that he doesn't get much by way of economies of scale to bring his production costs down. "Phil Holman" piholmanc@yourservice wrote: Frank Day. His last posts here were after a scientific study showed a statistically significant 1.5% gross efficiency improvement. The experts here still wouldn't buy it. wrote: No offense, but that sounds like 200 watts rising to 203 watts. Wouldn't that be 200W reduced to a mere 197 watts? -- Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 |
#35
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Beware of PowerCranks
"A Muzi" wrote in message ... Ride Faster wrote: I had the same experience with PowerCranks. This product is garbage. " wrote: It's really outrageous for them Powercrank to charge so much for a faulty design. "Tim McNamara" wrote The proprietor of PowerCranks used to post here to rebut criticisms, but I haven't seen anything from him for a while. Basically I suspect that the price is high because (1) he promises that his product will make you faster for which competitive people will pay lots of money and (2) his business is small enough that he doesn't get much by way of economies of scale to bring his production costs down. "Phil Holman" piholmanc@yourservice wrote: Frank Day. His last posts here were after a scientific study showed a statistically significant 1.5% gross efficiency improvement. The experts here still wouldn't buy it. wrote: No offense, but that sounds like 200 watts rising to 203 watts. Wouldn't that be 200W reduced to a mere 197 watts? No, but I know what you are getting at. For the same 200 watt output, VO2 consumption reduces by 100*1.5/E = approx 6% less. From this we infer that for the same O2 consumption, the athlete can output 212 watts. Phil H |
#36
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Beware of PowerCranks
"Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: wrote in message ups.com... On Jun 3, 5:46 am, wrote: On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman" Frank Day. His last posts here were after a scientific study showed a statistically significant 1.5% gross efficiency improvement. The experts here still wouldn't buy it. No offense, but that sounds like 200 watts rising to 203 watts. Well, the difference was in gross efficiency, not in power. Frank Day calls them PowerCranks, not EfficiencyCranks. Phil may know whether there has been a published RCT that shows an increase in power. I just checked their website and found another study of trained cyclists that showed a 15.6% increase in VO2max and an 11.6% icrease in max power. My understanding- which may not be correct- is that VO2 max is biologically determined and that training does not significantly change this. I'll assume you are talking about a theoretical ceiling and not the difference in the same athlete being in shape and not in shape. The theoretical ceiling is biologically determined but what biologically constitutes that ceiling is still up for discussion. As I understand it (it's been a while since I had any reason to look into this stuff and maybe new data has come to light in the interim), if your VO max is 60 ml/kg/min then that is basically it. You can't "train up" your VO2 by 15.6% at least from the data I had looked at a few years back. I'll resist the urge to challenge your understanding on the basis of a rider who loses 5 kg of body weight. When dealing with PCs, we are not interested in that aspect of any VO2Max improvement. That's good, because of course PowerCranks would have no different effect on this than any other cranks. That's simply a matter of weight loss. There is the argument that any improvement means the previous value wasn't the true max. Miguel Indurain's published VO2 max was 88 ml/kg/min which is very much at the high end. Lemond's was reported to be over 90 ml/kg/min. A training technique that would net guys think this a 15.6% increase would make them invincible. Nobody could touch them in an event like the Tour de France. You can't get even those kinds of gains by doping. You're not going to see those kind of gains in athletes who have maximized their training potential. In any event, VO2Max is a poor predictor of race performance within a strata of racing abilities. From the test, it is not clear whether actual 02 uptake was measured or if VO2Max was estimated from the time to exhaustion in the incremental test. VO2 is not the sole determinant of athletic performance- if it was, all we'd have to do is measure VO2 max and we'd know the winner. However, given that the literature used to indicate that VO2 was basically genetically determined- whether that is still the case I don't know- it seems highly unlikely that one can train up one's VO2 by 15.6%. http://www.ncbi.nlm.nih.gov/sites/en...RVAbstractPlus I think you've interpretted theoretical ceiling improvement to mean the normal kinds of improvements seen by athletes who employ new training techniques etc. Once again the "any improvement means the previous value wasn't the true max" argument applies. There are things you can train up by quite a bit, such as your sustained power output at lactate threshold, Wingate test, etc. Those things are important and can make a big difference in race results. Yep. Ive alluded to the fact that an appropriate test needs to be done with these things. I.e. measure what is directly attributable to racing performance. PowerCranks have always been marketed a bit too much like the Second Coming for my tastes. I thought you of all people could separate the science from the emotion. Hype annoys me, what can I say. When the hype seems mighty unrealistic, I get suspicious of there being a dose of snake oil in the mix. IMHO people who are extremely competitive have a tendency to be a bit gullible when it comes to things that promise improved performance. Of interest to me would be whether whatever benefits are gained from PowerCranks are durable. When people go back to regular cranks for racing, do the maintain the neuromuscular pattern that a PowerCrank is supposed to develop? Or do they go back to normal riding quickly? Do they have to "brush up" with the PowerCranks periodically? My hunch is that the muscle recruitment pattern is quickly unlearned and the rider goes back to a normal pedal stroke within a week or so after returning to using normal cranks. From my experience, it's subject to the same reversible process as regular training. How much fitness do you think you'll lose in a week? I haven't pedaled a PC in about 3 years but I can still employ the technique for sustained periods because I still maintain the riding technique with regular cranks. The purported unique benefit of PowerCranks is as much neurological as muscular. The rider has to develop a different pattern of muscle recruitment and develop new "muscle memory." That pattern of muscle recruitment is not necessary on regular cranks, and I suspect that the new pattern would be lost quickly- perhaps in a couple of rides. Now why would you think that? I can't think of one skill I've learned that has significantly diminished and especially not in a week. Do you suspect a loss in the ability to play the guitar in a week? This part of the debate is much like arguing tire RR with those that haven't read the article. I'm sure you can relate. Phil H |
#37
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Beware of PowerCranks
In article ,
John Forrest Tomlinson wrote: On Sun, 03 Jun 2007 19:26:41 -0500, Tim McNamara wrote: However, given that the literature used to indicate that VO2 was basically genetically determined- whether that is still the case I don't know- it seems highly unlikely that one can train up one's VO2 by 15.6%. An untrained person can, with training, increase VO2max that much. My understanding- which may be incorrect, I got this from an exercise physiologist that tested our team back in 1996 and maybe understanding has changed- is that you can't. You can change many other aspects of fitness with training, but you can't increase VO2 max per kg of lean muscle mass. You can increase your total VO2 by increasing your lean muscle mass, but not your ml/kg/min rate- which is the measurement that counts in endurance sports. Now, again, there may be newer information that contradicts this and I wouldn't know about it. I don't peruse the exercise physiology literature, especially since I stopped racing at the end of 2000... But once someone has been training seriously for some time they can't. And that is likely to be the target market for this product. |
#38
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Beware of PowerCranks
In article ,
"Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... In article , "Phil Holman" piholmanc@yourservice wrote: "Tim McNamara" wrote in message ... snip My understanding- which may not be correct- is that VO2 max is biologically determined and that training does not significantly change this. I'll assume you are talking about a theoretical ceiling and not the difference in the same athlete being in shape and not in shape. The theoretical ceiling is biologically determined but what biologically constitutes that ceiling is still up for discussion. As I understand it (it's been a while since I had any reason to look into this stuff and maybe new data has come to light in the interim), if your VO max is 60 ml/kg/min then that is basically it. You can't "train up" your VO2 by 15.6% at least from the data I had looked at a few years back. I'll resist the urge to challenge your understanding on the basis of a rider who loses 5 kg of body weight. When dealing with PCs, we are not interested in that aspect of any VO2Max improvement. That's good, because of course PowerCranks would have no different effect on this than any other cranks. That's simply a matter of weight loss. There is the argument that any improvement means the previous value wasn't the true max. Hmmm, I suppose but then we assume uncontrollable variables that make the comparative measurements useless. snip VO2 is not the sole determinant of athletic performance- if it was, all we'd have to do is measure VO2 max and we'd know the winner. However, given that the literature used to indicate that VO2 was basically genetically determined- whether that is still the case I don't know- it seems highly unlikely that one can train up one's VO2 by 15.6%. http://www.ncbi.nlm.nih.gov/sites/en...howDetailView& TermToSe arch=16876479&itool=EntrezSystem2.PEntrez.Pubmed.P ubmed_ResultsPanel.P ubmed_RV AbstractPlus I think you've interpretted theoretical ceiling improvement to mean the normal kinds of improvements seen by athletes who employ new training techniques etc. Once again the "any improvement means the previous value wasn't the true max" argument applies. Thanks for the cite. There were too many jargonicious terms in that abstract for me to sort out at 11:24 PM on a Sunday night. They're probably transparent to a physiatrist or exercise physiologist. snip Of interest to me would be whether whatever benefits are gained from PowerCranks are durable. When people go back to regular cranks for racing, do the maintain the neuromuscular pattern that a PowerCrank is supposed to develop? Or do they go back to normal riding quickly? Do they have to "brush up" with the PowerCranks periodically? My hunch is that the muscle recruitment pattern is quickly unlearned and the rider goes back to a normal pedal stroke within a week or so after returning to using normal cranks. From my experience, it's subject to the same reversible process as regular training. How much fitness do you think you'll lose in a week? I haven't pedaled a PC in about 3 years but I can still employ the technique for sustained periods because I still maintain the riding technique with regular cranks. The purported unique benefit of PowerCranks is as much neurological as muscular. The rider has to develop a different pattern of muscle recruitment and develop new "muscle memory." That pattern of muscle recruitment is not necessary on regular cranks, and I suspect that the new pattern would be lost quickly- perhaps in a couple of rides. Now why would you think that? I can't think of one skill I've learned that has significantly diminished and especially not in a week. Do you suspect a loss in the ability to play the guitar in a week? My comment on this comes out my background in psychology. I don't have a formal background in the sub-field of kinesiology- which would be relevant to the discussion- so it's quite possible I've got it wrong. The nervous system learns muscle recruitment patterns through repetition and indeed part of the training of any sport with repetitive movements is to refine that recruitment pattern. The pattern is maintained with repetition and decays with disuse. If you've had enough repetition, then you'll pick it back up quickly. I play guitar and the difference in my chops is noticeable to me if I don't play for a day. If I don't play for a couple days, it's painfully noticeable. If I didn't play for three days, you'd notice. If I don't play guitar for a week, which happens sometimes during the summer when I go out for a bike ride right after work and don't come home until dark, it takes me an hour or more of running scales and going through chord progressions to regain my customary level of fluency, for example. And I don't have to play a lot- a half hour a day or so- to maintain the motor skills (the creative skills are another matter :-P ). In the case of PowerCranks, my thinking is this: the average racer who buys these will already have had years of training on regular cranks with millions of repetitions of the pedaling motion. Average Racer buys the PCs, puts them on his bike and diligently follows the training protocol. He learns to lift his legs up and over the top of the rotation and into the power stroke. He rides with the cranks enough to develop the new muscular recruitment pattern and doesn't have to consciously think "up and over" with each pedal stroke. Thus he gains the signal benefit of PCs, which is that the leg pushing down through the power stroke isn't being resisted by the weight of the rising leg coming up through the rest stroke. Well and good. But in races and on group rides, he might switch to a bike with regular cranks due to various reasons. Now he doesn't have to lift that rising leg any more, and the long-established "normal" pattern of muscle recruitment would probably tend to rapidly reestablish itself- just like guitarists lapsing back into a familiar pentatonic scale in a performance setting rather than playing the Mixolydian scale that they've been learning to use in rehearsal. The question to me is "how durable is the new pattern of muscle recruitment" when the rider returns to normal cranks. An hour? A day? A week? A month? Once the pattern is established, does the rider have to use the PCs daily to maintain those cited gains in efficiency? I could readily imagine the rider falling back into a normal pedaling muscle recruitment pattern within 30 minutes. But I could also be entirely wrong on that, or there may be quite a bit of variety on a case-by-case basis. Interestingly PCs are the reverse of riding a fixed gear. The old belief is that fixed gear bikes are good for your spin. My experience, and that of most of the folks I have asked that do fixed gear winter training, is that when you get back on the freewheel bike you're pedaling squares and your spin is worse. The fixed gear's ability to raise the rider's leg with the momentum of the bike- which is part of what makes a fixed gear feel easier to ride than a freewheel gear of the same development- changes the muscle recruitment pattern fairly quickly. I've noticed it after a single midsummer fixed gear ride. So, in a roundabout way, that's why I would think that. Sorry for the excess verbosity and rather nonlinear approach to answering your question. This part of the debate is much like arguing tire RR with those that haven't read the article. I'm sure you can relate. I'm sorry to be a drag on the discussion. |
#39
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Beware of PowerCranks
On Jun 4, 4:07 am, "Phil Holman" piholmanc@yourservice wrote:
There is the argument that any improvement means the previous value wasn't the true max. and Once again the "any improvement means the previous value wasn't the true max" argument applies. Wouldn't that argument mean that if you did observe a change in VO2Max (in ml/kg/min) then the previous value was faulty and shouldn't be used as a basis for comparison? If one subscribed to that argument, both the improvement and VO2Max and the improvement in power should be discounted. "Tim McNamara" wrote in message VO2 is not the sole determinant of athletic performance- if it was, all we'd have to do is measure VO2 max and we'd know the winner. Well, it's true that VO2 isn't the sole determinant of athletic performance, but it's a better determinant than VO2Max: http://anonymous.coward.free.fr/rbr/coyle.png |
#40
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Beware of PowerCranks
On Jun 4, 6:20 am, Tim McNamara wrote:
You can change many other aspects of fitness with training, but you can't increase VO2 max per kg of lean muscle mass. You can increase your total VO2 by increasing your lean muscle mass, but not your ml/kg/min rate- which is the measurement that counts in endurance sports. You've answered your own question. Mass-standardized VO2Max is typically measured in terms of ml/kg/min, not ml/lean kg/min. |
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