Skyman wrote: "et me ask you, during your initial phase of PC riding, did you have quite a bit of fatigue in your hip flexors, both during and after riding? Did you feel this on your runs also? I am just not getting this fatigue that everyone talks about. In fact, while riding the PCs, the first things that I notice some fatigue developing in is my hamstrings and calves. Maybe Frank could also help with this.

Also, I have noticed when standing and pedaling and really putting force on the pedals, I will notice a slight slip in the cranks. In fact, this almost caused me to crash once as I was at the top of the pedal stroke and the crank slipped back slightly causing me to back-pedal unexpectingly. Needless to say, when sprinting, this can be a little hairy! Everything is tight so I don't know why it would do this. "

At expos, when putting new people on the cranks, about 75% feel them in the hip flexors, about 20% feel them in the ham strings, and about 5 % feel them in the Tibialis anterior. So everyone is different based on their background and specific weakensses. The HF's are so predominant in most people plus, when they are toast, they interfere much more in doing regular things like climbing stairs, that is why they are talked about so much. Yours are probably stronger than most because of your previous emphasis on hill running. That doesn't mean you won't benefit, although it may mean you may not benefit as much. Strong runners sometimes comment that the first running effect they see is not running faster, but, rather, not getting as tired when they run and recovering faster. I think running faster will eventually come but it may take longer and not be as dramatic.

The slipping you are feeling sounds more like a glitch in your coordination than a problem with the cranks. If you anticipate the pushing down before you are completely over the top, the cranks will go backwards. Remember, they will not allow any "cheating". On regular cranks you don't have a clue as to what you are really doing. It is this kind of feedback that will fix the coordination. That should go away with more use.

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Frank,
An original Ironman and the Inventor of PowerCranks

Tibbs wrote: Can I score some placebos off ya?

Don't know, Tibbsy...Doctor says he's coming, but you've gotta pay in cash...(from "Life in the Fast Lane")

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Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

Who ever said anything about thermodynamic efficiency? Wans't me. This is about the efficiency of the power applied verses the power outputed.

Yep force is not power, that doesn't discount what was said.

The low index was a result of not appling forces at the correct time or incorrectly appling forces and therby not yeilding power.

No, you are associating it, and incorrectly. You seem to be confusing the efficiency of the engine with the effectiveness of the power transfer. An example....put a worn out clutch in a car. Does that make the engine less or more efficient? NO, but it sure does affect the power being applied to the ground.

RVP, in case you missed my earlier post in your apparent abscence, instead of just plain avoiding the direct question I put to you, here it is again:

....extensors will fatigue, at a given work rate, well under VO2 max in a period of time....this could be two hours, or three hours, or even longer, depending upon numerous other factors...quit trying to put a time limit on the conditions of MY RIDER in MY QUESTION.

Since my cyclist is well under maximum cardiac output, well under VO2 max, and his extensors STILL FATIGUE after a period of time...it IS NOT fatigue due to cardiac output limitation.

Again, slowly, so hopefully you'll get the conditions and question straight....it IS NOT fatigue due to cardiac output limitations if he stays well under his maximum cardiac output, well under his VO2 max. Right? Right.

In this case...don't change the time frame to suit your arguement....why would it not be advantageous to train and use accessory muscles, such as the hip flexors, to assist in making the pedal go around.


This rider obviously has reserve cardiac output available. Even if the hip flexors are not as "efficient" as the extensors, there is NO CARDIAC LIMITATION reason why it would not be possible to provide blood flow to the hip flexors as they work to assist the extensors. IN THIS CASE, using trained hip flexors to assist making the pedal go around, either: the extensor work rate could be decreased and therefore they will work longer before fatigue; OR, IN THIS CASE, the rider would be able to go a little faster (however much faster the TRAINED hip flexor power would provide in speed) until the extensors fatigued.

Again, don't change the time frame...this rider has done everything he can to maximize his extensor function, etc. Let's say he has an International distance triathlon, and he knows he can put out only this certain rate of work with his extensors before he slows down in the time it takes him to complete the bike leg. Why wouldn't he benefit from hip flexor assistance?

JustCurious and I think he does benefit from such assistance. Leave PC's out of it, it's immaterial to the question.

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Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

Too slow,

I agree with your line of questioning but have one comment that I think alters the interpretation of the data. All of the forces on the pedal are not necessarily coming from muscle force. For instance, when we stand still on the ground we may be putting 200 lbf down onto the floor/pedals, but when standing the muscles can be relaxed.

And, the backward force on the upstroke, comes not from muscle force but the lack of it.

While your analysis does look at efficiency (if the direction of the forces were different there would be more energy delivered to the wheel for the same effort) it is not directly related to muscle force or effort. I think you understand that but may have missed this one point. It is quite possible that one of the ways PC's increase power is by this very mechanism, by changing the direction of the applied power because one cannot mash but must anticipate these direction changes. We won't know, of course, until someone studies it.

Frank

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Frank,
An original Ironman and the Inventor of PowerCranks

Frank, are you going to be at IMUSA? All this talk about PCs is making me curious. I guess that's the point, though :)

I will be at all the IMNA events this year, leave tonight for Disney.

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Frank,
An original Ironman and the Inventor of PowerCranks

Please someone, kill this thread. Regular cranks serve a purpose, PC's serve a purpose, fixed gear riding serves a purpose, Computrainer Spin Scan serves a purpose etc etc etc. You guys are all smart. The internet may soon shut down or Cisco/Juniper are going to have some major sales thanks for Frank and Rip !

By the way, I was the only powercrank rider at the morning 90K group ride. While I got dusted by a few riders (3) , I also dusted many (>20). On the biggest climb of the day, and the stage finish (this is a weekly series), I came out 4th both times. I'm sure Hincapie could have showed up with a single drive side crank, and done one leg drills and dusted us all.

My main point is that in biking and running, no matter how much you improve your technique and recruit ancilliary muscles, the guy with the biggest engine with reasonable technique will still beat a guy with an inferior engine and good form/technique (call it what you will).

In sport there is no silver bullet (OK, maybe EPO or darboproetin...but that is why they are illegal). Train hard, stay focused, eat well, sleep well and execute on race day. Everything else is fine tuning. These facts have not changed since they road the first TdF, did the first Hawaii Ironman or first Boston marathon.

You are correct that I brought up the efficiency. The efficiency of power transfer. The concept is simple. The subjects produced power. Power was transferred to the bike. Power is transferred to the ground. It is solely the transfer of power to the bike that I am referencing. The reason is simple, your focus is limited within the "subjects produced power" phase. You neglect the later two stages. These are important if we are discussing if power output (as measured at the rear wheel) can be improved.

You keep talking about "power delivered to the wheel" and how it differed between the two groups, but in fact it did not and cannot, at least in the isopower comparison. The point of the efficiency is how much power is generated by each subject in order to output equal power. This is what the IE is really telling us. My point is still valid at equal power output the subjects generated differing amounts of power.

What you're really trying to get at is how much of the energy liberated during muscle contraction was actually converted into useful work/delivered to the crank, but the amount of energy used to pedal is indicated by the VO2, not the index of effectiveness. No you are attempting to blend in issues. The first part of the sentence is correct. Some of these riders are generating huge amounts of power, that is NOT being transferred to the pedals. However, the indtroduction of the second part of the sentence confuses the efficiency of the engine with the effiiciency of the power transfer.

As I keep pointing out to you, it was the INeffective pedalers who were actually MORE economical. I have no problem stating that these subjects were more economical than the other subjects. You are just assuming, however, this is due to their style of pedalling, while you admit to the significant power losses that occur when pedaling.

One possible explanation for this is that they were INeffective at pedaling because they weren't contracting unnecessary muscles trying to reorient the forces being applied to the pedals (which do NOT reflect purely muscular forces). Due, I'm with you one this. But couldn't another possibility be that they just aren't as "efficient - in the physiological veiwpoint"? But in fact, the only reason they measured so high was due to a more effective pedalling style

Don't think that's really what I said...

What I did say...

"Force the flexor groups to unnaturally contribute to the pedal stroke because it's a more efficient or economical way to pedal - that's where your argument loses its validity."

and

"If your extensors are starting to fatigue you should recruit your flexors more. If your flexors are fried, you should rest them and use your extensors to a greater extent."

As for the second comment, It's only natural that we search for ways to sustain power while aleviating fatigue. I don't think that we can therefore conclude that alternate, disadvantaged muscle groups (flexors) should be used to delay or avoid fatigue in the more powerful, mechanically advantaged extensors.

What you really should be saying is that even in the most highly trained, PC adapted athlete the extensors will outlast the flexors. Therefore, we need to stomp on the pedals as hard as possible to delay fatigue in the weaker hip flexors and hamstrings.

Standard cranks are ideal for this type of training as they allow us to train that stomping action as much as possible without being limited by our mechanically disadvantaged flexor groups.

Curious,

What is unnatural about using your HF's? You climb stairs don't you?

Where do you get your data that says in the best trained PC'er the extensors have more endurance than the HF's? Once adapted, (which takes a certain amount of time to be sure - months usually, but seemed to take Skyman about 20 minutes) the endurance should be the same. The extensors may apply more force, but the endurance should be the same.

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Frank,
An original Ironman and the Inventor of PowerCranks

Who is hanging onto your ankle when using PC's or at any other time unless you have small children?

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Frank,
An original Ironman and the Inventor of PowerCranks

Not saying using the HF's is unnatural at all. Coyle's study seems to show that even the 'bad' pedalers put very little negative torque on the crank. So using the HF's does seem to come naturally to most.

What is 'unnatural' and most probably unproductive is emphasizing this contribution except when high, non-sustainable torque levels are required at relatively low cadences.

Curious,

Nothing about PC's emphasize the HF's. Where do you get that? All the PC's do is require, at a minimum, that the unweighting be complete. The reason the HF's get so much attention is this is the limiting muscle for most when they try to do it and they are surprised how limiting it is, at least for awhile. Beyond that simple unweighting, it is the riders choice how much to do more than that or not. So, using Coyles data, all PC's require is an extra pound or two of force, maximum, on the upstroke, over what is alreaady being done. What is the big deal or objection in that? Why would you object if a rider choose to use them more if that rider found it better to do so?

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Frank,
An original Ironman and the Inventor of PowerCranks

Dr. Winkle wrote: "My point, in other words, is that your "stair climbing" analogy is a poor one, as it fails to recognize the enormous differences in the size and therefore strength and power of the leg extensors and leg flexors. Or do you think that a PC-trained athlete could climb "stairs" upside down, with just a little help from some inversion boots or maybe some velcro?"

Rip, by this post, you clearly do not have a clue as to what the PC's really are, even worse than I thought. Your ignorance of the product is really showing.

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Frank,
An original Ironman and the Inventor of PowerCranks

No data, but I've yet to hear of a PC'er limping home while only being able to lift the pedals. Haven't heard of any PC'er crawling home, doing 50 situps, and not being able to stand up either.

I guess I have to rely on the absence of counter-anecdotal evidence to support my claim. : )

Of course the stories you have heard are in the unadapted. I have had customers be 25 miles from home and their clutch broke and they one legged it home and been no worse for the experience. What would you do if if 25 miles away from home and your pedal broke? Better hope you have a phone. It would be like taking a couch potato kid out to the starting line of a marathon and saying, you can do it kid and then concluding when he fails or crawls in that muscles in kids are weaker than muscles in adults who do marathons. One cannot make such statements unless one knows the muscles have been equally trained.

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Frank,
An original Ironman and the Inventor of PowerCranks

All of your 'data asking' privileges are now revoked until you produce some of your own (on anything). : )

[reply]back pressure probably isn't from muscular efforts because the thigh and leg probably weigh 20 lbs, so, if the back pressure is only 2 lbs, then the rider is actually unweighting 18 lbs. However, that two lbs of back pressure is two lbs of inefficiency. Doesn't seem like a big deal to just lift another 2 lbs does it to simply make it all go away, does it? Tell that to the average PC'er and watch them laugh at the statement.[/reply]

Been wondering about this - if the two cranks arms are unlinked - then surely you're lifting the 20lbs every time you pull up? So where does the "another 2 lbs" come from? We go from 2lbs to 20lbs work required of the HF and other muscles. Is this the training effect you ascribe the improvements to?

Nick