Pc+ct=ups

Triathlon Forum
28

Mr. Not wrote: "Offhand, I can think of 4 ways of testing the hypothesis that pulling up on the pedals is more efficient:

  1. compare subjects who pull up against those who don’t.

  2. eliminate the ability to pull up by testing individuals w/o their feet attached to the pedals.

  3. encourage people to exaggerate the tendency to push the contralateral leg up using a mechanical device (Rotor cranks).

  4. train subjects to pull up more (using one-legged drills, PCs, whatever it takes) and see what happens to their efficiency as a result.

Studies 1 and 2 have been done, and have shown no benefit to pulling. Study 3 has also been done, and found that exaggerating the tendency to push the other leg up actually resulted in increased efficiency. Study 4 has not been done, but given the results of study designs 1-3, the odds are low that any benefit would be found - and even if one was, you’d need appropriate controls to be certain that any such improvement was due to pulling up and not due to other factors. A good way of doing this would be eliminate the ability to pull up by dettaching the feet from the pedals - a study that has already been done."

I agree completely with your contention of the various ways of looking at this. I disagree with your contention that any of these has already been done.

  1. You apparently believe the Coyle study compares those who pull up to those that don’t. I disagree. While it appears that some in group two did pull up some, not all of them did and we don’t know how well these subjects could pull up (how long could they sustain single leg pedaling?). I know of no other study that shows this ability has ever been well learned by a large number of individuals using any particular technique (except for PC’s of course) although I admit it appears some have developed the ability but it is unrelated to current cycling ability, e.g, pro Robbie Ventura’s first ride lasting 5 minutes while amateur ttn being able to go 100 miles on day 3 and other amateurs and pros reporting first rides over an hour (such reports are rare though, even amongst the pros).

  2. You say this has been done, do you have a reference? Did it show being attached was advantageous? How do you interpret this if it does if view of your current view?

  3. I believe Rotorcranks work because they keep the contraction speed of the power muscles slower (the equivalent of pushing bigger gears and/or riding lower cadence) which makes them more efficient. I think the only tests that have been done on rotorcranks have been done to show there is an advantage, not to determine why. If you know of one how about a reference?

  4. Study yet to be done (although one was done at U Kansas that did show some efficiency/lactate/power improvement riding the PC’s 3 times a week for 6 weeks) but this study was never accepted for publication.

Until such studies are actually done, please stop trying to use studies that do not look at these factors to prove your point as no one takes your arguments seriously anymore. I welcome debate and scientific inquiry on my product. Based upon the multitude of anecdotal reports we have seen it would appear a study will confirm the effectiveness of the product to improve performance. Then the debate should, more appropriately, shift to the degree of improvement possible and how to best use them to achieve maximum improvement.

Frank

29

Frank asked about my butt. That was nice of him. My butt was a bit sore after 3:40 with PCs on the CT. BUT not much sorer than if I had been on regular cranks. This might be because, before PCs I peddled at 90-110 rpm in a light gear and, after PCs, I peddle at 60-70 rpm in a much bigger gear. In the big gears, I can feel some the weight being lifted off the seat. I only weigh 150 lbs so maybe that is easier for me.

But the butt thing brings up another point. Part of why I am faster with PCs is that they instructed me on the huge inefficiencies of high cadence. I now understand better why I cannot replicate what Lance does just by going to a low gear and a 113 cadence. It appears to me that a high cadence is only efficient if you can have high resitance, i.e., a big gear. I don’t know what gear Lance is in when he is at 113 rmp but I beatcha it is plently big. And I wager that if you put Lance in the gear I use to reach 113, his efficiency will plummet.

Bill

30

Power is work per unit time. Work if force through a distance. We can increase work by either increasing force or increasing distance (or both). When we have reached the limit of our ability to increase force the only way to increase power it so increase distance (cadence). It is that simple.

So, I think “optimum” cadence depends on power being generated. I think that is why most studies of optimum cadence tend to show cadences way less than what people actually ride, probably because these studies were done on poorly trained subjects. Optimum cadence for your grandmother who rides around the block once a week may be 45 because she is only generating 40 watts, whereas, for a professional who can generate 350 watts optimum may be 90-100.

An amateur who tries to ride like Lance but who can only sustain 150 watts is probably riding very inefficiently but they feel better because they look like they are riding more like Lance than their Grandmother (and they are encouraged to do so by “all” they cycling magazines), even though they would probably go faster if they rode more like their grandmother. Our ego can really interfere with our performance.

31

I might add that PC’s, by forcing the rider to pedal the entire circle, increase the distance of the force application, even if the applied force is “small” compared to the downstroke. So, with PC’s it is not necessary to increase cadence to increase power when at the limit of extensor force because one now has an alternative way of increasing the “distance” of the applied force per unit time. It is even possible (in fact natural) to increase power by decreasing cadence, because decreasing cadence allows for increased force to be applied to the pedals while keeping distance moved per unit time increased. As the capabilities of the new muscles improve, cadence will again increase as power increases. I think this is what almost everyone finds.

33

OK I bit. I looked over the paper. What I found interesting was the last line.

It appears that “elite-national class” cyclists have the ability to generate higher “downstroke power”, possibly as a result of adaptations stimulted by thier greater number of years of endurance training

I take this to mean that they (the elite-national class cyclists) were better as a RESULT of adaptations stimulated… man I wonder if there could be a way to cause adaptations to pedal another way???

Another thing that is real suspision about this study. The force pedals measured two dimensional forces (I was glad to see that), BUT no where was the graph of tangential force better know as F sub E portrayed. The results ONLY showed the torque being greater during the downstroke. It conveniently did NOT graph the resulting force vectors. This would be referred as F sub E We only see graphs of the vertical and horizontal components and not the tangential.

Oh yea one more thing left out of the conclusions but mentioned… Was the GREATER wasted power by the elite group. Look at the curves for the vertical force being applied. Look closely at the values for 0 and 180. At 0 it looks to be about 80N and for 180 it looks like an amazing 250N. This my friend is purely wasted power. Force being applied with NO torque produced. However if you look at group 2 you will notice they did in fact not only produced MORE torque at those positions, they did it with less forces being applied (taken from figures 6 & 7).

Pay close attention to group 1 subject A 141 watts with peak force of 515 N now look at E with 129 watts with a peak of only 395 N. Lets try the calculations please 91% of the power with only 76.7% of force. How did he manage to do that (I think he forgot to read the training manual). Look closely at the values for IE360, a much higher value (the effectiveness of forces applied - you know that dreaded F sub E that was not graphed). I would love to hear Not’s interpretation of this!! This ought to be good.

34

The “toe clip-no toe clip” comparison was also performed by Coyle - I’m sure you can find it with just a little digging through some of the journals at your local university library. The Rotor cranks evaluation to which I alluded was published recently in the ACSM journal. If you bother to look them up and read them, you’ll see that the data show exactly what I have claimed, just as the paper you have read does.

Yes, garbage is what I write, that is my word for it.

However, I wouldn’t classify your writing as garbage, just biased and inaccurate. It is as if you don’t know how to read a scientific study.

The Dr. Coyle paper, despite your continued insistence that it supports your position, does not do so. In fact, it suggests the possibility that increased pedaling effectiveness is beneficial…that’s Dr. Coyles’ observation!

Yes, it is in black and white…I suggest anyone interested to read the WHOLE THING (ah…the capitalization thing again!) and make up their minds for themselves. Don’t take my word for it, and certainly don’t take mr. admitidly biased’s (not a PC’er) word for it.

The reason I asked you to cite the references, is that I’d like to read the ones you are referring to, not just an article on the same subject. Because, I sincerely doubt your ability to accurately report on the statements in the article, based on your inaccuracies continually stated in regards to the Dr. Coyle article which you originally cited in this thread.

Cite the articles, I’ll read them and get back to you.

However, we both have the same conclusion about the original Dr. Coyle article in this thread, which is: everyone interested should read it for themselves and don’t believe the garbage I write, nor the obviously biased opinion of someone named “not a PC’er”.

36

TooSlow has a better ability to read and decipher the science in this article than I have. I didn’t know anything about F sub E or that two dimensional force measuring was a good thing…etc.

It is important that you had the wherewithall to read it for yourself, and not take my garbage nor “not a PC’ers” biased views as accurate.

Thanks for your contribution to reporting your view of the results found in a scientific article.

38

Although I enjoy Mr. Not’s role as devil’s advocate, could someone please send/loan him a pair of PCs for a few months. He might see the benefits of PCs and change his handle to “am a pc’er”.

Thanks to both sides for the wonderful debates so far. Have a great day everyone!

40

The only data you misrepresented that I can recall at the moment, is some comment about decreased oxygen utilization by not pulling up, or something like that. I don’t even recall exactly what it was you said, but, it came out of the blue and had nothing to do with the article being discussed.

I think while you state plenty of data accurately, you completely ignore the comments by the author, Dr. Coyle. as he explains some of the problems with looking only at the data obtained. Dr. Coyle says that increasing pedaling effectiveness (pulling up somewhat) was a power benefit in the slower, not as well trained, group 2. Dr. Coyle never said that increasing pedaling effectiveness would do anything about oxygen consumption in this study that I can recall, nor did he say that the better trained Group 1 riders wouldn’t benefit from increasing their pedaling effectiveness (pulling up somewhat). In fact, he suggested that Group 1 might do themselves a favor to work on pedaling effectiveness, but he didn’t know what the results would be.

For the record…I admit I write garbage, AND I also say that while focusing only on bits of data that support your own bias, you continually miss the author’s own discussion points that suggest the data points aren’t telling the whole story.

41

If this really is Dr. AC, he refused such an offer several months ago.

42

I accept that you are pulling the results of a couple of riders out of this study to prove your point. Unfortunately, this was not actually studied so your “proof” is anecdotal.

Further, (my main computer is down so I have lost access to the paper), it seems to me that the forces shown represents the forces at one point in time. I would be surprised if the “upward” forces demonstrated by a couple of the riders did not deteriorate or change substantially as the test progressed, but we do not know if they did or did not because this either was not measured or was not commented upon (as I remember). One of the major things new PC’ers have problem with is not pedaling in a “circular” fashion, but doing so for any length of time. Unless these participants have developed the ability to pedal in this fashion for sufficient periods of time, i.e., aerobically, they do not represent PC’ing and should not be compared. But there is no data given allowing one to know.

Again, while I don’t have the study in front of me I would be surprised if the three subjects you mention really developed more than 10% of their power on the upstroke. That would require them to produce about 20% of the downward force on the entire upstroke. (It would take 100% of the downward force on the upstroke to produce 50% of the power on the upstroke). I don’t remember the numbers being anywhere like this and being sustained for the entire upstroke in three different individuals.

I know you think this study is “convincing evidence” of your position, but it is clear that many of us think otherwise. It was a study that compared elite cyclists to not so elite cyclists and found that the elite cyclists could generate more power and had better blood supply to the prime movers. It does nothing to prove or disprove the ability of PC’s to improve the elite riders beyond what they can do without them or to make not so elite riders closer to elite riders, powerwise.

44

Mr. PCer(not) writes in part: "It is commonly believed that pulling up on the pedals makes you more efficient. I cited the O2 cost data in the Coyle paper because they do not support this belief.

…Coyle … In fact, he stated almost the exact opposite: “This finding (that performance was apparently not enhanced by group 2’s different pattern of force application) makes it unclear whether feedback devices (2,3,21) that allow a cyclist to improve pedaling effectiveness will lead to improved performance.” "

Mr. Not. Until you do this study comparing people who have adequately trained anaerobic muscles that must be used in circular pedaling into aerobic muscles, such that circular pedaling can be done aerobically, the conclusion you draw is invalid regarding oxygen utilization.

Further, even Coyle states that it is unclear if feedback devices would be useful in improving results. Only you seem to be able to draw the conclusion from this data that they are definitely not useful and a waste of time.

47

gentlemen, gentlemen, why must there be a thread like this every week? can’t you just agree to disagree? i guess it’s partly my fault as i start reading these hoping to pick up some new info, but it always ends up being the same conversation, citing the same articles, with the same arguments being raised on both sides. yes, i pc. i have noticed an improvement in my riding. is it the result of an honest to goodness physiological change and improved pedaling efficiency or me riding more in order to justify the expense? i have no clue. and i don’t really care. but i see no reason why these strings must continually pop up. it must seem obvious even to the non-pc group the dr. day isn’t trying to fleece anyone–he actually believes in the product and so do people that use them. isn’t that enough? i don’t know why some have a need to try to “prove” him wrong or discredit him. and there is no need for pc folks to constantly come in and try to convince others or defend themselves for using them. just agree to disagree and move on. end rant.

48

""Perhaps you should read the paper a little more closely and think about what was measured and reported: since crank length is constant, F sub E is equal to T sub C - which is the plot shown in Figure 4.

There’s absolutely no question that some individuals in the study were very skilled at pedaling in such a way so as to maximize the effective force vector. Subject K in particular stands out, with indices of effectiveness of over 80% during both the downstroke and the upstroke. There was, however, no relationship between how a person pedaled and their efficiency or their performance. This does not support the hypothesis upon which PCs and their ilk (PowerPedals) are based. “”

You are correct I read it too quick. The thought process was a little slow. F sub was the Force effective vector that created the applied torque, and that is graphed. My bad.

I shall attempt to restate with clarification for benefit to others as well.

The two dimensional forces are vertical and horizontal. Assume for a moment the pedal stays flat with the ground. A purely downward pedal stroke would show vertical forces with zero horizontal forces. Pedals may not remain flat (relative to the ground) during pedaling. Once a pedal is angled, you will generate both vertical and horizontal forces. (drive in your car and hold your hand out the window trick - the wind is only a horizontal force but your hand gets lift-vertical force). So all of those vertical and horizontal values must be converted into F sub E (force effective). Here is where I went bad in my previous thoughts/questions.

Force effective is that portion of the forces (vertical and horizontal) that cause the torque. No problems here, I admit this was indeed graphed.

We however skipped a step here, which is where I should have went but, in my haste, I did not. Remember that hand out of the window trick. Does your hand get lifted up or pushed back at an angle? At an angle of course. This is the force resultant vector. Draw a triangle with a horizontal line (representing wind) and then a vertical line (representing the lift created). Connect the two. The long side of the triangle is the force resultant (also know as drag in this case). (see bottom right page 96) Where does this lead us. Effectiveness of force applied.

F sub E - force effective / F sub R - force resultant = IE (indices of effectiveness). This is quite simply, did they do a good job at creating torque. You can supply as much vertical force as you want at TDC (top dead center) or BDC (bottom dead center) and no torque would be created (see figures 6 & 7 and my previous post). IE at these points would be 0% and any purely vertical force applied at 90 degrees would be 100%. If you can get all of the force applied to the pedals to generate an equivalent force effective, you would be most effecient at pedalling. Surely there can be no arguement about this. This is using the calculations and methods of determining effectiveness within this study (reference calculations and discussions on page 96 & 97).

Again I must admit I didn’t notice subject K. I have my suspisions about him to say the least. Group 1 - average Watts 124.5 with a peak force of 455.6 (IE360 = 63.5). Subject K looks like, well never mind, watts 127, peak force 320, IE360 = 80.7. (reference table 6)

Lets diasect the numbers shall we. Peak force applied to the pedals was around 70% of group 1. Hold on a minute!! The same power output with 70% less force required. Something must have driven this. IE360 was 27% better. Does this mean he was more efficient? In Mr. Coyles calculations, yes. So unless you consider same power with less peak force effective. How can someone create the same power (ok 2% more) with such low peak force values and peak torque values.

The only way is to have a higher IE360 (the highest in the group). How is that done, by maintaining a force effective that closely matches the force resultant. The only way to perform that little feat is to apply a mostly tangential force to the pedals. Better known as pedal in circles. Thanks you Mr. Coyle for giving us that little bit of info.

So I guess if we could get a graph of IE over the whole of the pedal cycle that would be interesting. I wonder just how much force is lost by applying only a downward force…verses a better application of force…

50

So are you proposing that the athletes in this study who pulled up significantly for up to 25 minutes did so with muscles that weren’t using any O2??

No, I am saying I would be very surprised if any of these individuals pulled up significantly for anywhere near 25 minutes. I believe they may have for a brief portion of this time when they were thinking about it but I doubt a single one of these riders rode like this for any significant period of time, and I can assure you that all the other PC’ers out there have the same doubts. How long did you say you could pedal one legged before you fatiqued? Less than 25 minutes I believe.

52

What is ironic to me is how you emphasize performance as the ultimate goal when stating your position on cadence, but when performance data are presented arguing against the idea of pulling up, you refuse to accept them. Quite a contradiction, no?

No. Until you can convince me that the subjects in group two were adequately trained to pull up as a PC’er does (and those in group one were not) then this paper is not an argument against PC’s. One of my contentions is that before PC’s it was simply was not possible to effectively learn how to pedal in circles for any length of time. If I am right in that contention (which essentially every PC’er would agree with) then the cohort in this study cannot be used to evaluate the effectiveness of PC’s or circular pedaling compared to “traditional trianing”. In fact, this study goes to suppport my contention that even the elite cyclists could not pedal in this fashion even though, I am sure, they had been training to do so. This study is worthless in this argument and just because you can find some evidence that one or two of these subjects pedaled at least some of the time in some semblence of circles is not evidence worthy of your certainty.

53

Mr. Not wrote: "You yourself have alluded to the fact that at least some people are able to almost immediately ride long distances using PCs - why do you find it so hard to believe that 3 or 4 out of 15 generally national caliber cyclists actually pulled up slightly while pedaling? "

Because that is 20-25% of the cohort which is way more than my experience of those who can do it well for an hour the first time, which is probably less than 2%. These numbers are well outside the norm so are totally unbelievable.

54

No I am pretty sure I have it quite right. I would suggest that you reread how the points were collected. And then the values shown in each.

page 94 right column - pedaling technique determined on the first day of testing…

page 95 left column - 1 hr testing performed to measure VO2 max.

page 96 left column - Samples were then selected from the first days effort based on varying degrees of VO2 max.

page 96 bottom right.- Then, and here is the interesting point, the data set was then chosen for the five revolutions where the angular velocity was nearest to 90 rpm. With no regards to VO2 max.

So we do not know at what level of VO2 max the technique was actually taken. It may be and judging from the data point collection method was a different level for some of the subjects.

Table 4 is therefore relavent to table 6. Table 4 does show the max power abilities of each cyclist however it does not corrolate to the data presented in table 6. As stated in the data point collection method above.

Table 6 - Power output per revolution is indeed the topic here. It is the seemingly contridiction of lower force to the pedals with a higher power (per revolution) that is important.

Once again I submit that K did indeed have the most effective pedalling style IE as calculated. Do you believe if subject E was able to reduce the peak force required to do the same amount of work he would be less efficient (495N E vs 320N K)? Come on K did the same amount of work with only 64.6% of required peak force.

Look closely at the depiction of forces, Force resultant is what was applied to the pedals and force effective is the portion that was able to turn the crank figure 1-b. IE means that for every 100 N of effort this percentage went to the cranks. That means that only 20N per 100 applied was lost by subject K, however group 1 lost an average of 36.5% of their power supplied.

Quite simply, hold on tight, if group 1 would pedal like K then then woud experience a 16.5% gain.

So if we look at table 6 group 1 although more capable of producing power during the 1 hr test, they required a peak force 23% more force to generate only 9.4% more power per crank revolution.

As to the graph of IE. It might be more correct to show the difference of force resultant and force effective. You would clearly see the wasted power produced by group 1. Figure 6 chart a 180 degrees pedal angle 0 degreees. Chart b 275 N vertical force. Chart c nominal horizontal force. IE at this point pretty darn 0. Force effective close to 0 / force resulting close to 225 N. (group 2 for the same point 125 N = much less wasted force) I now get the point, it is far more effective and efficient to flex the frame (which is all they are doing)

Group 1 is wating enormous amounts of power. Read the data before the conclusion, good point. Also understand the data points and values. Keep in mind that if the study was to prove a point, certain bits of information would not be made clear. Presented yes, clear no.

57

Mr. Not again retorts: "Perhaps one-fourth of those who have tried your cranks can’t match these results - but what about one-fourth of all the elite cyclists?

Another factor to consider is that these cyclists weren’t having to lift your heavy cranks arms using their hip flexors, nor did they necessarily have to generate a positive torque throughout the entire upstroke to keep “in synch”."

Honestly Mr. Not, your arguments make no sense to me. the cyclists you claim could pedal in circles were not the elite cyclists but the less than elite cyclists. Now, are we to believe that these less than elite cyclists could pedal this way either naturally or because they spent a lot of time working on it and then at some time determined that to get to elite status they needed to stop pedaling this way and start mashing? Or are we to believe that the elite cyclists once pedaled this way (at least some of them) and then consciously stopped because they wanted to get faster?

And, I take it that you seem to think that the only customers I have had are poor beginners trying to learn how to ride a bike. While I have had a few of them I would say the vast majority of the customers I have had would fit into your group b (serious people trying to become elites) and the next largest group would be equal to or superior to your group A (either in cycling or equivalently in triathlon or would you not put Bettini and/or Museeuw above any of them). Not a single one of these people told me that these were easy although I am sure some were able to ride fairly long time periods after short periods of time on them, as evidenced by some of the reports here.

Do you mean to tell the people on this list, that have tried the PC’s and gotten substantially better, that what they should do now is throw them away and relearn how to mash so they can pedal more like your group A and this will make them faster still. I tell you what, lets divide them up into two groups and one group will volunteer to do that and the other group will continue with the PC’s and see which group continues to get better faster, Let’s see how many takers there are for the give them up group.

Frank

58

I will wait for the grammer lesson…

I do notice how you did not however attempt to refute my comments. All of a sudden you cannot interpret a person’s writing. I must really be terrible at this or…

OK back to the study…

Table 7 if you please. The subjects produced an even amount of power 162 watts. The same pedal measurements. Lets look closely again at the data.

K - requires only 292 N peak force to produce 162 Watts.

Group 1 - average 416.9 N peak to produce the same 162 watts.

Please explain to me how group 1 was more efficient again?