Interestingly, the results track almost exactly to studies of various cadences. Slower cadences produce virtually identical deltas as the PC group. People on PCs ride slower cadences. A connection… or something overlooked in the study…?
Or if you really want to know if PC’s work - get a pair and try it out. I figure a study of 1 with me being the 1 would make me happy if it makes me faster! Of course, its a $700 experiment unless you send them back for the full refund at 2 months…
See my 2 week report - they are different - I’ll say that for sure…
I volunteer to be a research subject. Please send 1 pair of PC’s to me. No other compensation will be requested.
I was thinking the same thing. When I looked through the article, I noticed that it said the cadence was held at 80 rpm’s. If I am reading correctly, this means both groups used the same cadence, which would seem to support the PC’s as the mechanism to the increase rather than slower cadences. However, I wonder how they would control cadence on PC’s as from what I hear it is hard to pedal for more than a few minutes. So, I’m not sure both groups trained the exact same way. But that’s just with a quick once over of the article.
Cadence was kept constant (and the same) for both groups during the testing in order to control for this variable, if i remember right.
Assuming ‘GE’ or ‘Gross Efficiency’ is some relationship between oxygen consumption and power output, I’ll make the same argument I did during the cadence discussion a while back…
For an endurance athlete working at 69% of VO2max, consuming less oxygen for a given power output is NOT necessarily desirable as it could lead to earlier muscle glycogen depletion and an earlier onset of skeletal muscle fatigue. But I guess that’s only really relevant during a race or a competitive situation. Even after the adaptation everyone talks about, I don’t know why anyone would consider racing with PC’s. I may run hills in a weighted vest to train but it sure wouldn’t make sense to race in one…
As a training tool, on the other hand, I’d say the jury’s still out and the value of PC’s probably depends a lot on the individual… They’re probably much more valuable than spending equivalent time in the weight room for building cycling specific strength.
My 2 cents…
Curious wrote: “For an endurance athlete working at 69% of VO2max, consuming less oxygen for a given power output is NOT necessarily desirable as it could lead to earlier muscle glycogen depletion and an earlier onset of skeletal muscle fatigue.”
I must have missed this in earlier discussions where this was discussed or mentioned but I don’t understand why using less oxygen for the same power output (being more efficient) results in earlier muscle glycogen depletion and earlier onset of fatigue. I would have expected slower glycogen depletion and slower onset of fatigue.
Could you explain your reasoning here.
Cadence was kept constant (and the same) for both groups during the testing in order to control for this variable, if i remember right.
That would add important validity to the study. By my own testing, I can do 70% of VO2max wattage (~CP30) at 168 HR at 95 rpms, and at 162 HR at 80 rpms. While the lower rpms gives me a lower HR (and, presumably, greater efficiency), the higher rpms have a lower perceived exertion, and would be my choice of cadence in a TT.
I am told by knowledgeable people that, if I trained more at the 80 rpm, I would end up faster and would eventually prefer it.
Frank, did I read the abstract right that the ramp test showed no differences, but the 1-hour test did show a difference? Any idea why that might be so?
why using less oxygen for the same power output (being more efficient) results in earlier muscle glycogen depletion and earlier onset of fatigue. I would have expected slower glycogen depletion and slower onset of fatigue.
It’s a pretty consistent result in cadence testing that the lower cadence is more “efficient” in terms of O2 usage, but there is the sometimes surprising result that muscular fatigue sets in faster at lower cadences (wattage held constant, of course). I don’t know exactly why that is, but it’s been repeated a number of times. I have the same sensation in my own experience. As I wrote above, I can save oxygen at lower cadences, but my legs feel like putty faster.
I think that “fatigue” is more complicated than simply oxygen and glycogen usage.
Julian wrote: “did I read the abstract right that the ramp test showed no differences, but the 1-hour test did show a difference? Any idea why that might be so?”
I must say I found the result surprising for the degree of difference found between the groups. What surprised me was the degree of improvement maintained itself for the entire hour in view of what I considered to be minimal time on the cranks (1 hour 3 times a week).
However, I think the reason the ramp test did not show improvement was all of these tests were done on regular cranks. Therefore, there was not enough adaptation done to allow the new muscles to be used the entire period of the ramp test (when the subject was very tired) so the subjects reverted to old style pedaling and the limiters were the same.
Apparently, the 69% test did not stress these new muscles beyond their new capabilites, which allowed them to maintain the new efficiencies for the entire hour. I would have expected it to drop off at the end (in view of the “minimal” period of training), but it did not.
this could be a result of testing being done at cadences above or below what the subject “normally” rides. If the study were to look at what subjects could do after a period of time training at a new “normal” cadence for them, then the “perceived” effect might be different - or it might not.
I don’t know anyone that has done that so, it seems to me, that people make up theories to explain why people do what they do. I agree, however, that fatigue is a more complicated area than simple efficiency. It clearly involves a whole host of enzyme systems along with fuel and oxygen delivery.
However, it is hard to understand why the body, with appropriate training, cannot adapt to have the best fatigue resistance (endurance) at the most efficient cadence for them. I suspect that they simply don’t try, thinking that the most eficient cadence for Lance must be the most efficient cadence for everyone, even though everyone doesn’t train like Lance.
One thing the PC’s may do is force most riders to spend sufficient time at slower (“more efficient”) cadences that they adapt and learn to like them.
Curious wrote: “For an endurance athlete working at 69% of VO2max, consuming less oxygen for a given power output is NOT necessarily desirable as it could lead to earlier muscle glycogen depletion and an earlier onset of skeletal muscle fatigue.”
I must have missed this in earlier discussions where this was discussed or mentioned but I don’t understand why using less oxygen for the same power output (being more efficient) results in earlier muscle glycogen depletion and earlier onset of fatigue. I would have expected slower glycogen depletion and slower onset of fatigue.
Could you explain your reasoning here.
We beat this one to a lifeless pulp a couple of weeks ago…
and
That was an interesting thread and I am sorry I didn’t see it at the time to participate (although I am not so sure everyone here is as sorry about that as I).
You (or someone) raised an interesting question when you asked about whether PowerCrankers had a tendency to “bonk” when racing at the new found “more efficient” lower cadence. You invited people to post their experience but none did. Perhaps because they didn’t see the thread like me.
As far as I know there are a few people who have raced on PC’s for races as long as 1/2 IM distance. I have received no feedback that people “bonked” as a result. In fact, it is my sense that the tendency to “bonk” happens when the PC’er races on regular cranks and brings their cadence back up.
If this were the case this would be evidence against the assertion that higher cadences are “glycogen sparing” so less prone to “bonking” compared to “lower” “more efficient” cadences.
Some of you out there must have experience with this.
Frank
Here’s as non-scientific as it gets…I do not bonk at slightly lower cadences compared to before (since PC training, I race in the lower-mid 80’s…previously I raced in the middle-upper 90’s and even lower 100’s), and I now go faster during the bike…stand alone TT or triathlon, or duathlon. I run MUCH faster off the bike after riding at these lower-80 cadences…this is especially true in shorter races. I’ve only done a couple of half-ironman distances, but I had no pre-PC half-ironman race times to compare them to. However, being a non-runner, finishing with a top-40 half-ironman run split tells me the lower-mid 80’s bike cadence probably didn’t hurt my run much!
I don’t think that lower-mid 80’s cadence made my run faster, so I’m not advocating lower rpms for that reason. I think it is that I can pick my knee up higher due to PC training, and that is where my running speed increase came from.
My goal next year is to see if I can ease my cadence up a little more and keep the speed…my race results will dictate what rpm’s I end up using. We have slightly different physiologies, slightly different strengths, and slightly different weaknesses. So, it’s not surprising to me that we race better at slightly different cadences. Perhaps we will all gravitate to some majical area (like 90 rpm for example) as we all reach the same level of expertise…but, just because X rpm is best for the majority of the Pro racers, it doesn’t mean that X rpm is best for the good AGer, and what is best for the good AGer may not be best for the BOP AGer. Also, the individual differences allow for the “best” in any group to have some variation.
It takes time to do your own personal testing…but, don’t forget that it also takes a stopwatch! Perceived exertion, and Perceived Performance has fooled me too often to trust…the stopwatch doesn’t lie.
Yaqui,
there are a few things I think we can take away from your experience (especially if others see similar effects).
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A drop in cadence from the high 90’s-low 100’s to low to mid 80’s is not a “slightly lower” cadence in the eyes of most. That is a 15% drop.
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Second, the fact that you are now riding faster means you are putting out more power such that this drop in cadence is even more significant. I do believe that the higher the power the higher the “optimum” cadence. It is why it doesn’t bother me that Lance rides in the mid-90’s. It does not go against the concept. If you were riding at the same power as you were before, think how low your cadence would probably be using the new, more efficient style.
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I would expect your new “best cadence” to be somewhat higher next year although not as much higher than your speed is higher over what you did last year. Optimum cadence will increase with speed but not as fast as speed. At least that is my theory as to how things work.
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One thing I think those with no experience with PC’s don’t realize is that when you pedal in the PC style, the forces you exert on the down stroke are not greater (and may actually be smaller) than they were before at higher cadences, so some of their arguments about glycogen sparing, etc. with higher cadences may still be valid, assuming the style of pedaling doesn’t change.
but, just because X rpm is best for the majority of the Pro racers, it doesn’t mean that X rpm is best for the good AGer, and what is best for the good AGer may not be best for the BOP AGer.
I recently read a well-constructed study; the hypothesis was that the most efficient cadence will vary according to the power output, even within the same athlete. The research showed definitive evidence this is true. While the exact figures varied across subjects, the average results were something like 70 rpm for about 200 watts; 80 rpm for 300 watts; and 90+ rpm for 400+ watts. The higher wattages are best produced at higher cadences. Perhaps this is why Lance & Co. has figured out that he should pedal at 95+ when he’s on the attack…? Perhaps it also means that I might try cranking out my pathetic 175 IM-pace watts at a lower cadence…?
The authors pointed out that their result is consistent with other well-established testing of the relationship between the force exerted by a muscle and the speed at which the muscle contracts. Those two things multiplied equal power; lower one, the other must go up and vice versa. There is a nifty little curve one can plot, and one point on that curve represents the lowest level of energy to produce a given wattage. The cadences were lower than I would have expected.
Food for thought…
Do you have a reference? This supports everything I have been saying about cadence, power and efficiency. Need to put this study in my quiver.
Do you have a reference? This supports everything I have been saying about cadence, power and efficiency. Need to put this study in my quiver.
I’ll search the office tomorrow – it’s around somewhere. From a Canadian university group…
Do you have a reference? This supports everything I have been saying about cadence, power and efficiency. Need to put this study in my quiver.
Check the link - second to last post, page 2.
Cadence, power, and muscle activation in cycle ergometry. MacIntosh, Neptune, Horton - University of Calgary
Not sure how it supports what you’ve been saying about efficiency though… Rather than O2 consumption, they used muscle activation as their dependent variable. What’s missing is a comparison of optimum cadences at varying power levels as predicted by O2 consumption to those they found in this study by minimizing total muscle activation. My guess is the ‘minimizing O2 consumption’ optimum cadences at various power output levels would be measurably lower than the ‘minimizing muscle activation’ optimum cadences. I’d say your PC’s and the rider’s resulting lower cadence pedaling style may reduce O2 consumption at a given sub max power output, but you’re obviously doing it at the expense of higher muscular forces if power output is the same.
I’m not saying PC’s can’t be a valuable tool in a periodized training plan, but why would someone race with them?
Cadence being correlated to power generated makes sense. My low 80’s correlates to somewhere around 275 watts, guessing by my TT times, while Mr. Armstrong’s faster cadence certainly is done while producing much more power than I, and the RAAM riders at much lower cadence than mine are producing far less power than I. So, if I am to generate more power, I’ll probably have to do it at a higher cadence…I don’t know why it never seemed that simple to me before, but, it at least seems plausible. Add the individual variations to the mix, and it would still allow for a degree of variance in cadences…maybe one reason “ideal” cadence is so difficult to nail down.
JustCurious, one reason someone may choose to ride PC’s in a race is this: When you’ve put in a million pedal strokes the “normal way”, it takes a while to adapt to the “PC way”. This especially shows up when you become tired…either physically or mentally. If you can train away the physical fatigue, so that you aren’t physically limited by your ability to pick up that rising foot, racing on PC’s will remind your mind when it becomes tired…HEY, PICK UP THAT FOOT! Therefore, the increased efficiency of riding in the PC manner will be preserved, even at the later stages of a race. (I know, there is not a trademark on pedalling the way PC’s force you to pedal, and maybe some people can already do it without training on PC’s…although it’s doubtful to me…but, I hope you see what I mean.)