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Alright, I'm suckered into posting again... I knew it would happen... :)
I was predominately talking about fiber type recruitment though, not fiber type of biopsy. I don't think you will disagree with the statement that different cadences/intensities change the percentage of each fiber type that is recruited. For example, very low intensity efforts recruit more type I fibers. Very high intensity efforts (like sprints) recruit more type II fibers. I think that is well established. So what I was trying to say (but maybe did not say so clearly) is that here is what I think is a logical conclusion related to efficiency:
-> type I fibers contract more efficiently than type II fibers (but with less force)
agree
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-> the higher the required force of contraction (defined for cycling by torque - which is affected by both cadence and power), the more type II fibers get recruited.
I don't agree entirely here. there are two components to the required force of contraction. One is, of course, the force on the pedals. But, the other is the force required to accelerate the associated body parts up to the speed of the pedal. One component gets lower with higher cadence, the other gets higher. The timing of these various "forces" may not be entirely correlated but they are both present. This trade off probably explains why there is a range of cadences where efficiency doesn't change much. But, it is why unloaded high cadence cycling gets the old HR up and can take the cyclist anaerobic if one goes high enough even at zero power. This can also explain why better unweighting on the upstroke can increase efficiency because it could mean less recruitment of type II fibers when pushing with the quads, especially at higher power. Here is some pedal force data submitted to me by a PC'er comparing PowerCranks forces to what he does on regular cranks. He has lower pushing forces despite a lower cadence on PowerCranks at the same power (250 watts).
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-> each individual has a different breakdown of type I and type II fibers, though muscle fiber breakdown probably self selects somewhat. I.e., a natural sprinter is probably going to have a lot of type II fibers and a natural endurance athlete is going to have a lot of type I fibers
agree, it is why one of the most important aspects of becoming elite is chosing your sport correctly, not so much choosing your parent carefully.
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-> the variance in fiber type affects what is an optimally efficient cadence range for a given individual
that would be one component. But it is not the only one, imho.
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-> the most efficient cadence range will be the one that maximizes the use of type I fibers, since they respirate the most efficiently. However, for some individuals, they may to be able to generate 100% of the required force from type I fibers. In this case, type II fibers will be recruited. It's optimizing that balance that defines the most efficient cadence range. I.e., for individuals with a great deal of type II fibers, the optimal cadence range will be lower than for individuals with a lot of type I fibers. In everyone's case, however, a cadence that is either lower or higher than the ends of that range is going to be less optimal.
I presume you are talking about pure endurance events like Ironman. I am not sure I would agree with you here. I don't know there is any evidence to support this. People with high proportion of type two fibers probably are better off choosing another sport than trying to emulate Chrissie. I sincerely doubt Chrissie has a high proportion of type II fibers. I would think they would have to be even more careful about avoiding type II fiber use if they wanted to make it to the marathon.
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-> This is why as load goes up, the optimal cadence also goes up, because that is how you continue to recruit the maximum amount of type I fibers
Yes, but it is also why the time such a load can be sustained goes down. RAAM riders ride at a lower power and substantially slower cadence than "ordinary" cyclists. That argues against your (avoid type II use requires high cadence" hypothesis above.
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-> It's also why, as load goes DOWN, the optimal cadence also goes down, because there is a cost to simply pedaling (even against no load), and if the required force is small enough, then there's no reason to incur this additional load, since the required torque is already low enough.
Yes, I agree. the cost of pedaling against no load is the cost I mentioned above, the cost of accelerating the body parts up to speed (plus the internal friction of the various parts). As long as the forces involved are low enough that there is essentially no type I recruitment the cyclist should be able to pedal indefinitely. It is all about proper pacing, wouldn't you say.
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That's my opinion, which I believe is supported by my interpretation of various studies on cadence/efficiency/etc. So I hope that clears up why I was referring to fiber type. I was not talking about an individual's breakdown within a given muscle (though that is relevant because I believe it plays a role in determining optimal cadence range for a given individual at a given effort). I was talking about recruitment for a given load. I believe this is essentially what this study says (though I have not read the whole study, only the abstract):
The efficiency of pedaling and the muscular recruitment are improved with increase of the cadence in cyclists and non-cyclists. I'd also point to this study as one that stands in contrast with your assertion that most cyclists pedal with a cadence that is higher than their most efficient one (and that a lower cadence is more efficient). I do want to emphasize that I think it's a RANGE, not a number, where folks are optimal. This seems to be supported by efficiency studies that demonstrate an efficiency "plateau" across a range of cadences.
I would agree with your thoughts here that fiber type does affect what the athlete should be doing. I simply believe that most cyclists pedal at a cadence higher than is optimal for them because most of them are trying to pedal like Lance but none of them are training like Lance. Studies consistently show most efficient cadences in the power range of most athletes being between 60-80. Most people are racing at cadences between 80 and 100, IMHO. The athlete cannot know what is best for them without testing, and this doesn't require testing in the lab. It is simple trial and error to see what works and what doesn't, which is all Chrissie advocated that started this thread.
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Whatever she is doing she seems to think she can do it and it seems to be working for her. I don't disagree with that. I just think that's quite different from saying, "It’s a misconception that you need to spin a smaller gear at a higher cadence on the bike. You don’t, " Wellington said. " Doing that actually raises your heart rate and makes you more tired, which doesn’t serve you very well in long distance racing. Cranking it down and pushing a bigger gear lets me lower my heart rate." My dispute is with the conclusions she draws. That's my personal opinion. I think her conclusions about why low cadence is wrong. That's different than me saying that pedaling a low cadence is wrong. Chrissie is successful. Chrissie rides a low cadence. In my opinion, it's not reasonable to conclude that Chrissie is successful BECAUSE she rides a low cadence. Well, I think her conclusions are correct. Reasonable people can agree to disagree.
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Coyle wrote, Although during all laboratory measures of mechanical efficiency, cycling cadence was held constant at 85 rpm, this individual’s freely chosen cycling cadence during time trial racing of 30- to 60-min duration increased progressively during this 7-yr period from 85–95 rpm to 105–110 rpm. That is the change in cadence I am referring to. My *opinion* is that this training//racing cadence could impact his efficiency, even at lower cadences. "Carry over," if you will. I.e., training & racing at a very high cadence was what necessitated changes in pedaling efficiency. I.e., I'd argue that his pedaling efficiency changed as a result of changing his freely chosen cadence in training/racing. That's as opposed to saying that his cadence increased as a result of a change in pedaling technique. I.e., I would say that Lance's changes to his "preferred" cadence necessitated other changes, as opposed to vice versa. That's opinion. But I don't think it's unreasonable to argue that the ~10% increase in preferred cadence was a physiological load that his body responded to. yes, Coyle did write that. And Carmichael wrote that they started in 1993 on a deliberate attempt to change his pedaling dynamic in order to allow him to ride at a higher cadence. High power requires high cadence. The more efficient one is the higher one can take the cadence, the longer one can sustain that cadence, and the longer one can sustain that power. It is what makes Lance a champion, IMHO, not drugs. At least, his dominance can be explained without the need to invoke drug use to the dismay of Ashendon, whether he has used them or not.
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Before one would want to show that improvement in time to exhaustion was a result it would be nice to show that the dynamic was changed. One step at a time don't you think. I would actually have gone the other way. In my opinion, if time to exhaustion was improved, then that is of value even if the dynamic doesn't carry over. I.e., performance is the currency we care about. If there isn't a clear performance benefit, then who cares if there's carry over. That's my thought process. I just don't see that carry over is all that interesting if you don't actually know that there is a benefit that you are trying to understand in the first place. <shrug>
Well, when you do your study you can do it that way. We are all stuck with what the researchers actually do even though we might like them to do something different.
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1sec is "instantaneous" enough for my purposes. I.e., given what I stated I believe, it isn't important to me to have feedback more often that that. In fact, I actually run a 5sec rolling average, which is still works "instantaneous" enough for me. Again, that's based of my belief about how PowerCranks could add value to training, which is based off no personal experience, but which is based off discussions with elite athletes I am close friends with who have used PowerCranks in the past, but do not use them now. I also don't agree that PowerCranks offer a "more efficient" pedaling style. Other than that rather large sticking point, we are in agreement. If you want to race on PowerCranks, train on them (and vice versa). But I don't thinks it's been demonstrated conclusively that PowerCranks offer a more efficient pedaling technique. If you want to say that people *perceive* that they pedal more "efficiently" as a result of using PowerCranks, I don't really have a problem with that. But I don't think you can conclusively say that pedaling in the PC style is more efficient. One step at a time, as you said.
But, in 1 second the crank has made 1.5 revolutions and there have been 3 "pushing" events by the two legs (at 90 rpm). How on earth does that kind of feedback help the rider to change the way he pedals. And, whether you believe PC's improve efficiency or not something has to explain the improvements reported by users. Luttrell obtained an efficiency improvement in only 6 weeks so it is possible. Burns almost replicated that result in 5 weeks but the improvement didn't quite reach statistical significance. With enough time though . . . Problem is no one has ever before shown that it is possible to reliably improve cycling efficiency which makes these results improbable to the experienced researcher. But, then there is that Lance data fly in the ointment.
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I think most will agree she tends to ride at a lower cadence and faster than most of her competition. I'm not so sure. That's really why I've asked for numbers. If you watch either Tereza Macel (4th) or Lucie Zelenkova (lead out of the water), both pedal with a lower cadence than Chrissie. That's why I brought up her riding at 88rpm. It may appear that she rides a low cadence, but what is her average over the course of a race? I don't know. But I was - personally - quite surprised to see how high her cadence was during the first couple hours of the race. I'm not asking you to explain it. I'm just saying maybe she doesn't actually pedal at as a low a cadence as she thinks. Reminds me of when folks use to say Bjorn rode at 65rpm. He actually did some races at 85-90rpm average, but people on the sidelines still said "look at him grinding away." I think there is some influence of people seeing what they want to see. That's all I'm saying.
Well, it is the concensus of most that she rides at a lower cadence. I can tell you this, that #2 told me she also tries to keep her cadence low. No spinning for her.
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I also disagree that saying "ride a lower cadence and see if it lowers your HR, because that's better for endurance racing" is good advice. I.e., if she'd said "ride a lower cadence and see what it does for your bike speed and run sped off the bike," then that's fine. It's really the issue of concluding that a lower cadence = lower HR and that lower HR is definitely better for endurance racing. That's my opinion. It seems to differ from yours. That's fine.
Reasonable people can agree to disagree. It is hard to disagre with Chrissie's results though. If she thinks something is important to her result I guess it is possible she might be wrong but I think one would be foolish to entirely discount it.
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Frank,
An original Ironman and the Inventor of PowerCranks