What is the evidence that training with power is superior to . . .

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The point of the original question is whether this improved specificity actually makes a difference in outcome. Only if you believe about 90% of sports science research it does!

Nice one Frank, attack Power Meters as they stand between you and credibility for your product. Now attack one of the strongest principles of fitness as it also disproves the claimed benefits of your product.

Perhaps you missed the "science" link. None of them prove our 40% 9 month claim but two show substantial, statistically significant, benefits.In areas not related to riding the bike faster.

Did I mention that I also don't do weights, big gear efforts, high cadence efforts, expect to climb faster by just riding the flat. I follow the time tested (and researched) plan of get fit then get specifically fast!

So, it is not all anecdotal. And, I, at least, am trying to get the studies done to "prove" the 40% claim.So you make a claim then look for the proof to back it up. Congratulations Frank, PT Barnum would be impressed that Jujucrank buyers fall for this.

Is anyone actually interested in looking at whether the improved specificity of power meter training actually results in improved outcome. What is this Power Meter Training that you speak of. I don't think anyone is training dramatically differently to the past. Get fit, get fast. We just know exactly what we need top train for and have a better way of measuring it.

Power is less invasive than HR? and, again, the question is, what is the evidence it is "more effective"?Putting something on your bike verses putting a chest strap on.

I know because I can do efforts on my bike from 10-20mins and have the same heart rate but power varies by 20-40 watts.

The Australian MTB team used to use HR to track their racing efforts and because the heart rate curve did not change they thought MTB was a steady state effort. Till they got SRM and saw that power varied hugely and changed to a more more interval orientated programme.

With pursuiting on the track we could look at heart rate and say it is similar (very high static heart rate) and just train at a constant pace. But depending on the track used we can see big drops in power as riders go through the bends on tracks like Invercargill NZ which has tight bends but lower drops on Manchester as the bends there are easier to ride.


So, you are against riders improving cycling efficiency, even if a method existed that allowed them to do so? Is that what you are saying? Why can't a rider improve both fitness and efficiency? Wouldn't that be a better goal
As long as the efficiency makes then a faster bike rider. Becoming more efficient at squatting large weights, playing tiddlywinks or using Jujucranks hasn't been shown to do that.

TPeople ask me for "proof" of my claims all the time. It seems to me that other claims should be subject to the same scrutiny.Extraordinary claims demand extraordinary evidence. Power meters claim to measure power. I'm convinced that they fulfill this modest claim, because I have a layman's understanding of some of the physics. You, on the other hand, are making extraordinary (actually, ridiculous) claims for your JujuCranks: your infamous 40% claim. For years, you made these claims without anything that could be called evidence. Now, you have dug up some evidence that doesn't come aywhere close to supporting the claims you're making (40%!), and yet you're still happy making them.


Also, my web page is not filled with nothing but anecdotal reports. There are actually a few scientific studies which we have comments on. Perhaps you missed the "science" link. None of them prove our 40% 9 month claim but two show substantial, statistically significant, benefits.Note that having done studies that show an effect, but do not show your ludicrous 40% effect, is positive evidence that your 40% claim is false. You don't get to keep rolling the dice until you like the numbers that come up.

To quantify this 40% claim, for those who don't train with power, Dr. Day is claiming that a pair of floppy cranks can give a so-so cat 4 (W/Kg of 4.2) the power output of an outstanding international pro (4.2 * .14 = 5.8 W/Kg) in 9 months. This is wishful thinking, or greed, on the part of your clients, and either idiocy or fraud on your part.

And, I, at least, am trying to get the studies done to "prove" the 40% claim.I'm sure you are, since you'd be able to buy a lot more tanks of gas for your Porsche if such a study "got done." Of course, that's the opposite of how honest science happens. Real research starts with a plausible hypothesis, and then sets out to test it. You've not even reached the level of a plausible hypothesis with this crack-smoking "40%" routine, because there is no possible mechanism that fits our current understanding of how riding a bike works that would make a 40% bump in power conceivable.

I know I won't convince Dr. JujuCranks, but for those playing along at home, what he's claiming is, to the best of anybody's current understanding, physically impossible. He might as well claim his cranks will make you able to fly, or 10 feet tall. For any modestly trained cyclist, 1.4 times FTP is way, way over VO2Max power. Rider to rider variations in efficiency (how much oxygen the rider uses to produce a given amount of work) are fairly tight: on the order of 20-25%. Coming from the very low end to the very high end would get you 1.2x. The other 20% would not be achievable without improving cardiac output by about 20%. I don't think Dr. Day has any explanation for how this massive leap in cardiac output would occur due to a different pattern of muscle recruitment. Unless the JujuCranks are transdermally leaching EPO into your blood stream through your pedals?

To quantify this 40% claim, for those who don't train with power, Dr. Day is claiming that a pair of floppy cranks can give a so-so cat 4 (W/Kg of 4.2) the power output of an outstanding international pro (4.2 * .14 = 5.8 W/Kg) in 9 months. Sorry to respond to myself here, but using myself as an example: my "trained" FTP is about 280W. A 40% increase would be 392 W.

My trained FTP gets me to the top of Old La Honda, a local benchmark climb, at around 20 minutes: a respectable time, but not enough to hang with the front group on the local hammer ride. It's a steep enough climb that times scale close to linearly with power, so doing it at 1.4x the power would mean doing the climb in about 14:20, which would smash Eric Heiden's decades long record of 14:50 by 30 seconds or so.

Not. Gonna. Happen.

Extraordinary claims demand extraordinary evidence. Power meters claim to measure power. I'm convinced that they fulfill this modest claim, because I have a layman's understanding of some of the physics. You, on the other hand, are making extraordinary (actually, ridiculous) claims for your JujuCranks: your infamous 40% claim. For years, you made these claims without anything that could be called evidence. Now, you have dug up some evidence that doesn't come aywhere close to supporting the claims you're making (40%!), and yet you're still happy making them.You don't seem to realize how difficult it is to get a good study done that would look at the claims that take 6-9 months to realize to "prove" the claim. We have plenty of evidence to suggest the claim to be true but we can't "prove" it.

So, our claims are what improvements we expect our average user to see, if they use them exclusively in training, for that period of time, not what has been proven. I understand such a claim is extraordinary. So, we do something we consider extraordinary as a result, as a way to answer those with doubts. We offer an unconditional 90 day money back guarantee. Try to get that from any other performance improvement device or scheme.

If you are so insecure that you do not feel capable of judging for yourself as to whether the improvements you are seeing (or not seeing) in that period of time (or shorter, you don't have to wait the entire 90 days to send them back) are worth the investment what have you lost? But, if we are right, what have you gained? What are you so afraid of? I have never seen such a bunch of insecure egos.



Note that having done studies that show an effect, but do not show your ludicrous 40% effect, is positive evidence that your 40% claim is false. You don't get to keep rolling the dice until you like the numbers that come up.Let me get this straight. You are saying that a study that lasts 6 weeks, that shows positive results but it doesn't show the famous 40% result, is POSITIVE evidence proving the 40% claim, that requires 6-9 months of use to see, is false? Is that what you said? Where did you go to school?


To quantify this 40% claim, for those who don't train with power, Dr. Day is claiming that a pair of floppy cranks can give a so-so cat 4 (W/Kg of 4.2) the power output of an outstanding international pro (4.2 * .14 = 5.8 W/Kg) in 9 months. This is wishful thinking, or greed, on the part of your clients, and either idiocy or fraud on your part. Thanks for your helpful insight.


I'm sure you are, since you'd be able to buy a lot more tanks of gas for your Porsche if such a study "got done." Of course, that's the opposite of how honest science happens. Real research starts with a plausible hypothesis, and then sets out to test it. You've not even reached the level of a plausible hypothesis with this crack-smoking "40%" routine, because there is no possible mechanism that fits our current understanding of how riding a bike works that would make a 40% bump in power conceivable. Sure there is. All one has to do is analyze all the losses between the muscle contraction work and the work done at the wheel. If you analyze those losses you will see that many of them can be reduced or eliminated. You have simply accepted the "story" that the losses between the contractile efficiency of the muscle of above 40% and the gross efficiency of the cyclist of about 20% is just something that happens. A 40% improvement in efficiency simply improve the average cyclist from an efficiency of 20% to 28%, well under the muscle contractile efficiency - and would account for a 40% power increase in and of itself. Then, of course, you have the additional possibility of incorporating more muscle into the pedal stroke. Now, I suspect, even you would not deny that involving more muscle mass could increase power output. So, if it is possible to incorporate more muscle and increase efficiency at the same time, improving power 40% actually becomes pretty easy.


I know I won't convince Dr. JujuCranks, but for those playing along at home, what he's claiming is, to the best of anybody's current understanding, physically impossible. He might as well claim his cranks will make you able to fly, or 10 feet tall. For any modestly trained cyclist, 1.4 times FTP is way, way over VO2Max power. Rider to rider variations in efficiency (how much oxygen the rider uses to produce a given amount of work) are fairly tight: on the order of 20-25%. Coming from the very low end to the very high end would get you 1.2x. The other 20% would not be achievable without improving cardiac output by about 20%. I don't think Dr. Day has any explanation for how this massive leap in cardiac output would occur due to a different pattern of muscle recruitment. Unless the JujuCranks are transdermally leaching EPO into your blood stream through your pedals?Well, it may be "physically impossible" to the current understanding of those who have not experienced the cranks. But, it certainly is not "physically impossible" to the many customers who have experienced such gains. Go back and read some of the posts of Swampy. If you have never used the cranks you simply do not know what you are talking about.

A 20% increase in Cardiac Output is actually pretty easy to hypothesize. Cyclists tend to be on the low end as athletes go, when compared to rowers, XC skiers and other athletes who use more of their total muscle mass in aerobic, endurance sports. CO adapts to how many muscles are being exercised, otherwise all athletes would tend to be at about the same limit with a little genetic variation. It is simple, if we can increase the number of muscles the cyclist is using, the CO, and VO2max, and all those other things, will increase also. Not so hard to hypthesize, if you will simply think about it. Something you have obviously not done.

Sorry to respond to myself here, but using myself as an example: my "trained" FTP is about 280W. A 40% increase would be 392 W.

My trained FTP gets me to the top of Old La Honda, a local benchmark climb, at around 20 minutes: a respectable time, but not enough to hang with the front group on the local hammer ride. It's a steep enough climb that times scale close to linearly with power, so doing it at 1.4x the power would mean doing the climb in about 14:20, which would smash Eric Heiden's decades long record of 14:50 by 30 seconds or so.

Not. Gonna. Happen.Well, that is almost exactly the improvement reported to us by a rider in Spain who was formally tested at about 6 months intervals in assoication with starting training on the PC's. In 13 months of exclusive use his FTP improved from 284 watts to 394 watts. And, his VO2max went from 71.2 to 85.5 ml/kg (although some of that improvement came from a 4 kg weight drop). Oh, and he set a personal best on a climb outside of Madrid that he set 14 years earlier when he was lighter and competing more seriously. What are you afraid of? Does speed or getting better frighten you? Or is the thought that there is something out there you don't understand that frightens you and keeps you from, at least, trying them.

one legged pedaling (as most people do it) is so far removed from good pedaling technique (and what PC's force someone to do)

What is good pedaling technique and how does a PC'ers full 360 pedal stroke differ from that of a one legged pedaller. If a self confessed stomper like A. Coggan trained seriously on only PC's for over a year until he had the circular technique fully perfected, would he increase his power output over that of stomping and disprove the results of Coyle.

You don't seem to realize how difficult it is to get a good study done that would look at the claims that take 6-9 months to realize to "prove" the claim. We have plenty of evidence to suggest the claim to be true but we can't "prove" it. That's kind of the funny thing about extraordinary claims. If your claim were close to true, you wouldn't really need a study to convince me: 40% would be like EPO squared. Your users would dominate the sport to the complete exclusion of all other athletes. Every-day athletes like me (20 minutes up OLH) would suddenly be crushing long-standing records (14:20 up OLH). The world would beat a path to your door, and you'd have no need to pound the table shouting "40%" to no-talent pedal pushers like me in internet forums. Yet here we are.

But again, I've gotten sucked into arguing whether or not your cranks "work." I know why I don't believe they work, and I have already heard your wishful thinking about how they might work. There's not much more ground for us to cover. What I hope to convince you of, is that even if your cranks do all you say and more, your method of selling them is indistinguishable from the method that a charlatan would use. You behave exactly the way I'd expect my hypothetical "FloppyBar" hawker to behave, and that will keep at least me from ever trying your product. I am not interested in wasting 90 days of my limited training time to try every product that someone claims will work miracles (would you give FloppyBars 90 days, just because I say so?), and that user reports of improvement are suspect (almost all cyclists improve from year to year, and self-deception effects are strong), I (a potential customer) am stuck judging the product from your presentation of it.

And you offer impossible claims with weak evidence. You talk openly about "getting studies done" that show the effect you "know" is there. You say that you "cannot judge them unless you've tried them," which I'll have to remeber once I get my FloppyBar business off the ground. You might not be a charlatan, but for years now, you've walked like one and quacked like one. What else am I to conclude?

In 13 months of exclusive use his FTP improved from 284 watts to 394 watts. And, his VO2max went from 71.2 to 85.5 ml/kg (although some of that improvement came from a 4 kg weight drop).I claim that a rider with a VO2max of 71.2 and a 284 W FTP is either micropscopically tiny, or not a trained cyclist.
What are you afraid of? Does speed or getting better frighten you? Or is the thought that there is something out there you don't understand that frightens you and keeps you from, at least, trying them.I dunno, Frank. Why are you afraid to try FloppyBars? I'll even give you money back guarantee: exclusively ride with them for the next five years, and if you're not 700% faster over all terrain and distances I'll refund your money.

That's kind of the funny thing about extraordinary claims. If your claim were close to true, you wouldn't really need a study to convince me: 40% would be like EPO squared. Your users would dominate the sport to the complete exclusion of all other athletes. Every-day athletes like me (20 minutes up OLH) would suddenly be crushing long-standing records (14:20 up OLH). The world would beat a path to your door, and you'd have no need to pound the table shouting "40%" to no-talent pedal pushers like me in internet forums. Yet here we are.

But again, I've gotten sucked into arguing whether or not your cranks "work." I know why I don't believe they work, and I have already heard your wishful thinking about how they might work. There's not much more ground for us to cover. What I hope to convince you of, is that even if your cranks do all you say and more, your method of selling them is indistinguishable from the method that a charlatan would use. You behave exactly the way I'd expect my hypothetical "FloppyBar" hawker to behave, and that will keep at least me from ever trying your product. I am not interested in wasting 90 days of my limited training time to try every product that someone claims will work miracles (would you give FloppyBars 90 days, just because I say so?), and that user reports of improvement are suspect (almost all cyclists improve from year to year, and self-deception effects are strong), I (a potential customer) am stuck judging the product from your presentation of it.

And you offer impossible claims with weak evidence. You talk openly about "getting studies done" that show the effect you "know" is there. You say that you "cannot judge them unless you've tried them," which I'll have to remeber once I get my FloppyBar business off the ground. You might not be a charlatan, but for years now, you've walked like one and quacked like one. What else am I to conclude?I don't have to convince you of anything. I tell you what we think our average user will see and we tell you why. We admit we do not have proof, nor do we claim that everyone will see such benefits. The better you are now the less likely you will see such benefits, but the worse you are the more likely your benefits will be greater. So, it is unlikely that any mid-pack rider is going to set any world records in 9 months. They will be much closer to these elite riders, but they will not pass them, especially since many of the elites are training on the device also.

Anyhow, you can choose to ignore what I say. Spend your thousands of dollars on your PM (I think we have one customer who owns 8 SRM's) when there is no evidence it offers anything superior in results than what was available before.

I have nothing against PM's. Even people with PC's have to train some way. Training with power is the way some of them choose to train. I can see how a PM might make it easier to judge effort and do other things. I can see why a coach might like them as they have something concret to know what their athletes are actually doing. But, I simply started this thread asking the question as to what is the evidence, if any, that it is a superior method of training, when it comes to results. You folks were the ones who contaminated this thread with all the PC attacks, apparently because you didn't like the thought that it was becoming apparent that there is no evidence to that end. So, attack the messenger.

Did Merckx use these floppy cranks? Has anybody markedly successful ever used them?

Nope.

Did Merckx use these floppy cranks? Has anybody markedly successful ever used them?

Nope.Before you are so sure with your NOPE answer to your question you might want to review a list of riders using them. A fair number of national and world champions whose names you might recognize are on the list. But, then, I am not sure of what your definitions of "markedly successful" is. :-)

What is good pedaling technique and how does a PC'ers full 360 pedal stroke differ from that of a one legged pedaller. If a self confessed stomper like A. Coggan trained seriously on only PC's for over a year until he had the circular technique fully perfected, would he increase his power output over that of stomping and disprove the results of Coyle.There is a substantial difference between one legged pedaling and PC pedaling. In one legged pedaling it is necessary to apply force on the upstroke to drive the bicycle, to keep it going at a steady speed. When pedaling with PC's it is not necessary to apply any force on the upstroke to keep the bike at a steady speed as the bicycle is kept at a steady speed during the "upstroke" by the opposite leg, which is now on the downstroke. All that is necessary is to completely unweight on the backstroke plus a gram or two to get the cranks up. That is way different than pedaling with one leg, plus the rider is balanced in the saddle, something that doesn't happen with one-legged pedaling usually. Another thing that is different is one-legged pedaling is usually done at very low cadences of 30-50. PC'ing can be done at normal cadences, albeit not for very long in the beginning.

Of course, it is possible to apply force on the backstroke with PC's but most people do not. It is enough work for most to just increase the potential energy of the leg from the down to the up position (which the rider gets back as power to the wheel on the down stroke). So, the rider is doing substantial work on the back stroke, just not applying much force to the pedals.

If A Coggan trained on the PC's for a year, he would definitely increase his power. Only question is by how much. He is at the pointy end of the stick so it probably wouldn't be by 40%, but I bet it would surprise him (actually, any improvement would surprise him, I am sure).

Before you are so sure with your NOPE answer to your question you might want to review a list of riders using them. A fair number of national and world champions whose names you might recognize are on the list. But, then, I am not sure of what your definitions of "markedly successful" is. :-)

Where's the list? And why don't you use conventional advertising where you befriend potential buyers? Irritating and badgering doesn't seem to work.

And why so down on power meters? They don't compete against your product. If you want to persuade people with figures, which seem to be what people here give credence to, why not use a PowerTap to prove how effective Power Cranks can be?

I think you need to re-examine your marketing technique. Persuade us with results measured with a power meter. They can be your ally, not competitor!

I don't doubt the effectiveness of improving the up stroke, it's just that your approach has put off a lot of your potential market and in this game, as in many, word of mouth is vital.

If A Coggan trained on the PC's for a year, he would definitely increase his power. Only question is by how much. He is at the pointy end of the stick so it probably wouldn't be by 40%, but I bet it would surprise him (actually, any improvement would surprise him, I am sure).
But we come back the findings of your studies that people become better at using Jujucranks but it doesn't help them to ride faster than those using normal cranks and doesn't make them better on normal cranks and can actually make them worse.

Plenty of good research showing that trying to replicate your intended sporting movement (baseball batters using overweight bats, sprinters running downhill) can actually have negative effects.

Anyone with a powermeter can tell you that training on the flat doesn't make you a better climber. Track riders heading to Beijing are flocking to tracks around the world that are a similar shape to the track there so they can prepare specifically for their events (not sure if they will have smog pumped in to be truly specific).

So if Cadel wins the tour this year it will be in spite of using Powercranks. Just like Hayden Godfrey. Who won a World Title this year on the track although he is producing less power than the past. Just lucky they made a track event (Omnium) that suits him down to the ground.

Where's the list? And why don't you use conventional advertising where you befriend potential buyers? Irritating and badgering doesn't seem to work.

And why so down on power meters? They don't compete against your product. If you want to persuade people with figures, which seem to be what people here give credence to, why not use a PowerTap to prove how effective Power Cranks can be?

I think you need to re-examine your marketing technique. Persuade us with results measured with a power meter. They can be your ally, not competitor!

I don't doubt the effectiveness of improving the up stroke, it's just that your approach has put off a lot of your potential market and in this game, as in many, word of mouth is vital.Where is the list? Well, for starters you could try our web site if you were interested in finding out some of the names, but, since you asked, I will drop a few names for you. Bettini, Evans, Rogers, Leipheimer, Hincapie, Museeuw, and on and on and on on the cycling side. The current Italian National time-trial champion (Pinnoti) is even blogging at out site and another Italian to pro (Ricco) posted a Youtube video of him riding the cranks and talking about the upcoming season (which is how we found out he was on the cranks). But, what do these people know about cycling that you don't know?

Today Peter Cannell won the US National ITT for 30-34 by more than 2 minutes, averaging over 29 mph for the 38 km course. He started training on the cranks in October of last year.

I am not down on PM's. It just seems that many think they are the cat's meow when it comes to training and racing and many of the biggest advocates (some even having written books on the subject) seem particularly down on my product. I simply asked the question as to whether there is any real evidence that might justify such a view regarding the superiority of PM's as training or racing devices. Because there seems to be no "satisfactory" answer to this group, some here decided to attack me and my product for simply asking the question? So be it.

But we come back the findings of your studies that people become better at using Jujucranks but it doesn't help them to ride faster than those using normal cranks and doesn't make them better on normal cranks and can actually make them worse.

Plenty of good research showing that trying to replicate your intended sporting movement (baseball batters using overweight bats, sprinters running downhill) can actually have negative effects.

Anyone with a powermeter can tell you that training on the flat doesn't make you a better climber. Track riders heading to Beijing are flocking to tracks around the world that are a similar shape to the track there so they can prepare specifically for their events (not sure if they will have smog pumped in to be truly specific).

So if Cadel wins the tour this year it will be in spite of using Powercranks. Just like Hayden Godfrey. Who won a World Title this year on the track although he is producing less power than the past. Just lucky they made a track event (Omnium) that suits him down to the ground.Ugh, getting better is not just about power. It is about going faster than your opponent. That can also involve endurance (which is where efficiency might play a big role) and aerodynamics, which can adversely affect power.

So, Cadel is not going to win the tour because he is simply been on PC's for about 5 years or so but because he has integrated them into his program in a way to make him a superior cyclist. Getting good involves a lot of hard work. PC's is just one tool towards that end. If you choose to ignore its potential, that is your choice. But, it would appear, he has not. If he thought they were useless I am sure he would have sent them back 5 years ago and told us to stop using his name. He did not and he has not. You, on the other hand, have never used them but, somehow, seem to be able to declare them useless. Who should people be listening to?

Ugh, getting better is not just about power. It is about going faster than your opponent. That can also involve endurance (which is where efficiency might play a big role) and aerodynamics, which can adversely affect power.
Endurance, power over time.

Aerodynamics, improving how you use your power.

But there are many factors that lead to a result.

You, on the other hand, have never used them but, somehow, seem to be able to declare them useless. Who should people be listening to?
It's just making a informed decision based on the research and knowing what is really important for cycling and what isn't.

All that is necessary is to completely unweight on the backstroke plus a gram or two to get the cranks up.

Where in the 1 to 12 o'c pedaling circle does a PC rider stop unweighting ?

Where in the 1 to 12 o'c pedaling circle does a PC rider stop unweighting ?The PC rider cannot stop unweighting before TDC. If the pedal is moving up they need to be unweighting. I guess it is theoretically possible to stop or reduce the unweighting a little before TDC if they are pushing forward with enough force such that the combined force is still forward. But, watching people get tired, if they stop unweighting early and anticipate the down stroke, the pedal goes backwards.

Fday..I think it's sad that you've used "this forum" for PC marketing purposes. At least that's what I think..after reading 50% of the replies and based on your original question which prompted this ridiculous perpetual thread. Besides, you might want to cease before it gets ugly and you either say something you regret..or someone else does...if they haven't already.