The pedaling technique thread

[veganrob]

lol. nice.

 

[coapman]

Insanity: doing the same thing over and over again and expecting different results.

Albert Einstein

From Ti Designs on The Paceline Forum,


The conclusion I've reached about pretty much all of the studies is that they don't understand cycling, so they use valid tests to come to stupid conclusions. Take the OP's video for example, the title of this thread is "Clipless pedals 4 percent less efficient". No they're not. They are at least as efficient as flat pedals as long as the rider doesn't use them in a way that wastes energy. So, you've shot down the idea that pulling up adds power to the pedal stroke, or the cost/power ratio sucks - anyone who's done and one leg drills should know that.

The next conclusion they would come to is that flat pedals are just as good as clipless - assuming that there is only one state in cycling, the one they tested. Just about every study I've ever read left me wondering if any of them have been on a bike. There are a few labs at Harvard that study locomotion, I have invited them to extend their testing to real world conditions and group dynamics. Thus far I don't think any of them have ventured outside of the lab...
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[coapman]

http://www.scientificamerican.com/article/mathematical-impressions-the-bicycle-pulling-puzzle/

 

[coapman]

Alex, Hamish, and Hugh:
Have you guys noticed that this forum is always you rational guys vs. coapman and FrankDay? What percentage of the posts on this forum come from the five of you? 90+%?
You, the rationals, try to debunk things but you just can't win. Every thread is a Tar Baby.
Also, I have recently developed a suspicion that coapman doesn't really believe anything he posts. Rather he is trolling to see how much of a response he can get out of you rational guys. He thinks to himself "How can I really push their buttons?" If I'm right he must get tremendous entertainment.
Try not posting to this forum for six months and see what happens. At worst the other two will post some silliness but no one will pay any attention. I reckon the forum will be nearly dormant.
Of course, if you enjoy these arguments then by all means keep it up. Finally, remember that all press is good press. So every time you guys respond to a post about a certain product you are doing FD a favor.
Cheers,
Jim

Just because scientists failed to decipher the simple biomechanics of the perfect pedalling technique, does not mean it does not exist.
https://www.youtube.com/watch?v=7hh2DcgpnkU

 

[coapman]

Just because scientists failed to decipher the simple biomechanics of the perfect pedalling technique, does not mean it does not exist.
https://www.youtube.com/watch?v=7hh2DcgpnkU

I may have missed it and this may be OT, but did you ever do a diagram showing muscle force generation vs fixed hip, knee and ankle fulcrums vs the fixed BB and crank / pedal fulcrums to explain how maximum torque can be applied at 12 O'clock?
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I don't need to because the same muscles are used in exactly the same way as indoor Tug o' War men use their muscles to apply maximal forward and downward force from their shoe to the mat. This means the cyclist's shoe at 12 o'c will be in a level or slightly pointed down position depending on forward or rearward position on saddle.

 

[JayKosta]

...
I don't need to because the same muscles are used in exactly the same way as indoor Tug o' War men use their muscles to apply maximal forward and downward force from their shoe to the mat. This means the cyclist's shoe at 12 o'c will be in a level or slightly pointed down position depending on forward or rearward position on saddle.

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In the tug-o-war example, yes the participants are attempting to exert their maximum 'forward' force that they can, and the 'downward' force only needs to be sufficient to prevent slippage.

I believe they can be very powerful in that specific sitiuation and movement, but how it relates to a continuously changing pedaling technique is not obvious. What makes you think that the 'forward force' they produce at 12 o'clock is greater than the 'downward force' they would be able to produce on a pedal at 3 o'clock?

Jay Kosta
Endwell NY USA

 

[King Boonen]

I would have thought maximum force was applied somewhere between 12 and 2?

 

[coapman]

I would have thought maximum force was applied somewhere between 12 and 2?

That's possible but it depends on the timing of the release of that forward force. You have also to take into consideration that the crank will be decelerating between 9 and 11 and for the smoothest and most effective technique this has to be righted asap.

 

[coapman]

----------------------------------------------------
In the tug-o-war example, yes the participants are attempting to exert their maximum 'forward' force that they can, and the 'downward' force only needs to be sufficient to prevent slippage.

I believe they can be very powerful in that specific sitiuation and movement, but how it relates to a continuously changing pedaling technique is not obvious. What makes you think that the 'forward force' they produce at 12 o'clock is greater than the 'downward force' they would be able to produce on a pedal at 3 o'clock?

Jay Kosta
Endwell NY USA

From a seated pedalling racing drops position possible forward combined muscle force at 12 is greater than what the quads can generate around 3 but when you merge both these forces you end up with the same torque at 12 as at 3.Your brain has only to concentrate on each leg from 11 to 5. In the same way as the T o'W men make maximal use of their arm muscle power a cyclist can also avail of the necessary arm power resistance for his forward force at 12. This is best done with SCOTT RAKE aero bars using left and right leg/arm action alternately, unlike Anquetil who was forced to use double handed resistance, causing him to move forward on saddle when maximal force was being applied.
A cyclist can use this combined upper and lower body muscle power to drive his crank forward and down, the T o'W men use it to drive themselves backwards. The T o'W men are doing it in slow motion, that's the only difference.

 

[Dear Wiggo]

I may have missed it and this may be OT, but did you ever do a diagram showing muscle force generation vs fixed hip, knee and ankle fulcrums vs the fixed BB and crank / pedal fulcrums to explain how maximum torque can be applied at 12 O'clock?
__________________


I don't need to because the same muscles are used in exactly the same way as indoor Tug o' War men use their muscles to apply maximal forward and downward force from their shoe to the mat. This means the cyclist's shoe at 12 o'c will be in a level or slightly pointed down position depending on forward or rearward position on saddle.

You do need to. Just as you need to draw the force vectors for the tug of way to see why it is completely different to cycling. I double dare you.

So far there are 2 ways for you to prove your hypothesis: vector drawings, and torque measurements from SRMs.

You are shying away from both because you are scared of the truth. Embrace the fear and the truth.

 

[FrankDay]

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In the tug-o-war example, yes the participants are attempting to exert their maximum 'forward' force that they can, and the 'downward' force only needs to be sufficient to prevent slippage.

I believe they can be very powerful in that specific sitiuation and movement, but how it relates to a continuously changing pedaling technique is not obvious. What makes you think that the 'forward force' they produce at 12 o'clock is greater than the 'downward force' they would be able to produce on a pedal at 3 o'clock?

Jay Kosta
Endwell NY USA

The tug of war example is really a bad example. Yes, the foot forces are forward when compared to the earth but because the athlete is leaning backwards (45º or more?) the actual force relative to the body is actually "down". Further, in the tug of war position, the athletes legs are mostly straight, not bent as they are at TDC when riding a bicycle, and they are both doing the same thing. It may be how Coapman thinks about his technique but it has nothing to do with what he is doing or even trying to do. A better example of what he is trying to do are the forces involved in kicking a ball with the knee bent (maximum forward foot force with zero downward pushing force).

 

[FrankDay]

That's possible but it depends on the timing of the release of that forward force. You have also to take into consideration that the crank will be decelerating between 9 and 11 and for the smoothest and most effective technique this has to be righted asap.

If we think of the crank as a rotating disk (which it behaves as if both cranks are connected together) there is no acceleration or deceleration. You are thinking of the pedal speed upwards decelerating but, at the same time, it is accelerating forward. As a result the pedal speed remains constant. It is the fact that the pedal is constantly changing direction that makes applying "optimum" power so difficult.

 

[coapman]

The tug of war example is really a bad example. Yes, the foot forces are forward when compared to the earth but because the athlete is leaning backwards (45º or more?) the actual force relative to the body is actually "down". Further, in the tug of war position, the athletes legs are mostly straight, not bent as they are at TDC when riding a bicycle, and they are both doing the same thing. It may be how Coapman thinks about his technique but it has nothing to do with what he is doing or even trying to do. A better example of what he is trying to do are the forces involved in kicking a ball with the knee bent (maximum forward foot force with zero downward pushing force).

It does not matter what way the body is leaning, the muscle action from hip to sole of foot is what's important, it does not change. The t o'w technique can generate both forward and downward maximal force which is ideal for merging purposes as your crank moves from 12 to 3. The ankle and lower leg play a vital role in this technique as your applied maximal force retains 100% tangential effect from 12 to 3 while working in unison with the necessary arm resistance.. Your example of kicking a ball demonstrates you have not the slightest idea of what's involved, it can only produce minimal torque at TDC and no force at 1 o'c, that kicking force is coming from the knee, my force comes from the hip.

 

[FrankDay]

Your example of kicking a ball demonstrates you have not the slightest idea of what's involved, it can only produce minimal torque at TDC and no force at 1 o'c, that kicking force is coming from the knee, my force comes from the hip.

If you would ever take the time to do those force vector diagrams, as suggested by others, you would see that at TDC the hip is pretty much restricted to providing force either up and down. It is the knee, at TDC, that generally provides force forward.

 

[coapman]

If you would ever take the time to do those force vector diagrams, as suggested by others, you would see that at TDC the hip is pretty much restricted to providing force either up and down. It is the knee, at TDC, that generally provides force forward.

It is not the hip alone that generates the power at TDC, it is the combination of almost all muscles from hip to ball of foot that does it, using arm muscles for resistance. Do PC'ers use that kicking style at TDC



Quoting from Cyclingnews "Lance's agile, toes down pedaling style may be visually reminiscent of 5 time Tour De France Champion Jacques Anquetil. Cyclingnews discussed Lance Armstrong with Jean-Yves Donor. Mr. Donor covers cycling for Paris daily Le Figaro and is head of the International Association of Cycling Journalists. We asked Donor if the comparison of Lance with Anquetil is appropriate.

"Well, not really," said Donor. "Anquetil was a elegant rider who was really a time trial specialist in his day. His riding style was so smooth he looked like he was just sailing along. Anquetil was very powerful in his rear end, and used this to drive his pedaling, while not moving his upper body."

 

[FrankDay]

It is not the hip alone that generates the power at TDC, it is the combination of almost all muscles from hip to ball of foot that does it, using arm muscles for resistance. Do PC'ers use that kicking style at TDC

They do if they are applying any forward force at TDC (which they must if they get the crank across the top). The only question is how much force?

Quoting from Cyclingnews "Lance's agile, toes down pedaling style may be visually reminiscent of 5 time Tour De France Champion Jacques Anquetil. Cyclingnews discussed Lance Armstrong with Jean-Yves Donor. Mr. Donor covers cycling for Paris daily Le Figaro and is head of the International Association of Cycling Journalists. We asked Donor if the comparison of Lance with Anquetil is appropriate.

"Well, not really," said Donor. "Anquetil was a elegant rider who was really a time trial specialist in his day. His riding style was so smooth he looked like he was just sailing along. Anquetil was very powerful in his rear end, and used this to drive his pedaling, while not moving his upper body."

Ugh, that quote says nothing about Anquetil's pedaling forces/style other than he was very smooth and had good core strength. Unless someone actually measured Anquetil's pedal forces they (and I suspect you) are just guessing as to what he was actually doing. Oh, and BTW, one's "rear end" (the glutes) would be used to push the pedal down and, perhaps, pull it back" but not to push it across the top.

 

[JayKosta]

If we think of the crank as a rotating disk (which it behaves as if both cranks are connected together) there is no acceleration or deceleration. You are thinking of the pedal speed upwards decelerating but, at the same time, it is accelerating forward. As a result the pedal speed remains constant. It is the fact that the pedal is constantly changing direction that makes applying "optimum" power so difficult.

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Yes, the acceleration/deceleration of the rotational speed of the cranks around the BB spindle is small whenan effective type of 'smooth' pedal technique is used.
But if there really was NO accel/decel of the cranks, then the power would be equal all the way around the crank rotation, unless somehow the forces that inhibit forward speed of the bike are pulsing up and down in sync with the crank rotation.
Also is there was no accel/decel, then independent cranks would be easy to use because neither crank would ever 'fall behind' the other.

Jay Kosta
Endwell NY USA

 

[FrankDay]

============================
Yes, the acceleration/deceleration of the rotational speed of the cranks around the BB spindle is small whenan effective type of 'smooth' pedal technique is used.
But if there really was NO accel/decel of the cranks, then the power would be equal all the way around the crank rotation, unless somehow the forces that inhibit forward speed of the bike are pulsing up and down in sync with the crank rotation.
Also is there was no accel/decel, then independent cranks would be easy to use because neither crank would ever 'fall behind' the other.

Jay Kosta
Endwell NY USA

Actually, I think the variation is pedal speed is small even when one doesn't have a smooth pedal stroke. It is so small it can be effectively constant, which is why I used that term, even though it isn't constant. Most (all as far as I know) assume pedal speed is constant. What little variation in pedal speed there is is accentuated by use of non-circular chain rings. It is these variations in speed that contribute to some of the inaccuracies of power meters.

 

[coapman]

Actually, I think the variation in pedal speed is small even when one doesn't have a smooth pedal stroke. It is so small it can be effectively constant, which is why I used that term, even though it isn't constant. Most (all as far as I know) assume pedal speed is constant. What little variation in pedal speed there is is accentuated by use of non-circular chain rings. It is these variations in speed that contribute to some of the inaccuracies of power meters.

It may be small but in TT's where seconds count I estimate that deceleration effect of the pedal/crank when using circular or mashing styles is almost treble that of Anq's semi circular technique.

 

[FrankDay]

It may be small but in TT's where seconds count I estimate that deceleration effect of the pedal/crank when using circular or mashing styles is almost treble that of Anq's semi circular technique.

This speed variation is the basis of the Computrainer Spinscan calculation and display. Because we are only dealing with the mass of the wheel and fairly high rolling resistance the variation in wheel/pedal speed is much larger than seen on the road and even then it is almost imperceptible to the eye (although you can hear it in the whir, whir, whir change in pitch of the wheel sound). Most people have a spinscan number (the ratio of the average torque to the max torque) in the 60-75 range. The very smoothest riders would have a spinscan number in the 90's.

 

[coapman]

This speed variation is the basis of the Computrainer Spinscan calculation and display. Because we are only dealing with the mass of the wheel and fairly high rolling resistance the variation in wheel/pedal speed is much larger than seen on the road and even then it is almost imperceptible to the eye (although you can hear it in the whir, whir, whir change in pitch of the wheel sound). Most people have a spinscan number (the ratio of the average torque to the max torque) in the 60-75 range. The very smoothest riders would have a spinscan number in the 90's.

Let's say each of a rider's legs was capable of applying continuous equal torque from 12 to 6 o'c and no torque from 6 to 12, what would his Spinscan number be.

 

[FrankDay]

Let's say each of a rider's legs was capable of applying continuous equal torque from 12 to 6 o'c and no torque from 6 to 12, what would his Spinscan number be.

100

10 letters

 

[coapman]

100

10 letters

This means you can get nearest to the ideal pedalling technique by concentrating your power application on only 180 deg.of the pedalling circle.

 

[FrankDay]

This means you can get nearest to the ideal pedalling technique by concentrating your power application on only 180 deg.of the pedalling circle.

Spinscan is a measure of smoothness, not a measure of perfection. So, no, this means you can only get a perfectly smooth pedaling technique applying force only 180º of the arc and only if one could do what you specified. Of course, the example you gave is impossible to actually do so, of course, it is not possible.

 

[coapman]

Spinscan is a measure of smoothness, not a measure of perfection. So, no, this means you can only get a perfectly smooth pedaling technique applying force only 180º of the arc and only if one could do what you specified. Of course, the example you gave is impossible to actually do so, of course, it is not possible.

That is impossible but what is possible is you can apply close to maximal torque for 150 deg. and effective torque for the remaining 30 deg.