The importance of crank length to the cyclist.

[coapman]

Sigh. This has been discussed many times before. Let me post again a graph showing actual pedal forces done by the same rider (obviously incompletely trained) riding at 250 Watts. This rider worked at UC Davis so had access to their force pedals so decided to test himself and see what was happening.

Most of the big changes occur across the top and bottom and eliminating the negative forces on the upstroke. As a results of these seemingly small changes in this portion of the stroke the rider doesn't need to push nearly as hard to maintain the same power.

The blue is what I call pedaling in circles. The green is closer to what most people do and, while close, doesn't qualify for that definition in my book.

I asked for the differences if any between circular and PC pedaling, not pc pedaling and mashing.

 

[FrankDay]

I asked for the differences if any between circular and PC pedaling, not pc pedaling and mashing.

I asked you to define what you mean by circular. You have yet to do that but once you do then I will be able to tell you the difference. In fact, you will be able to tell yourself by comparing your definition of circular pedaling to what the blue dynamic is above.

 

[coapman]

I asked you to define what you mean by circular. You have yet to do that but once you do then I will be able to tell you the difference. In fact, you will be able to tell yourself by comparing your definition of circular pedaling to what the blue dynamic is above.

It's exactly the same as your definition. Described by some as rolling your foot over a barrel at the top and scraping mud off your shoe at the bottom with slight pulling up or unweighting during the upstroke. There should be no negative torque around the circle. The problem or weakness with the circular technique arises when a rider applies maximal possible power, while the additional minimal torque around the top and bottom of the circle will not increase from what you have shown in that example, the effort and concentration used around the top and bottom and any pulling up will result in a weaker downstroke. That's why mashing is more powerful. Now how does the ideal circular style differ from PC pedaling?

 

[FrankDay]

It's exactly the same as your definition. Described by some as rolling your foot over a barrel at the top and scraping mud off your shoe at the bottom with slight pulling up or unweighting during the upstroke. There should be no negative torque around the circle. The problem or weakness with the circular technique arises when a rider applies maximal possible power, while the additional minimal torque around the top and bottom of the circle will not increase from what you have shown in that example, the effort and concentration used around the top and bottom and any pulling up will result in a weaker downstroke.

Really? Your support for such a statement? I submit we can train ourselves to use pretty much any pedal force pattern we want as long as we get the proper feedback and put in the effort. I can devise ways of emphasizing the top, bottom or even back if anyone thought that might be better or to even encourage a perfectly tangential power application but would there be an advantage? The question is what is best and most powerful? The only thing I can see that makes any obvious sense to pursue (although it is not obvious to everyone) is eliminating negative forces.

 

[coapman]

I can devise ways of emphasizing the top, bottom or even back if anyone thought that might be better or to even encourage a perfectly tangential power application but would there be an advantage?

You already did with Powercranks and claimed they gave a 40% power increase, now you are asking, would there be an advantage.

 

[FrankDay]

You already did with Powercranks and claimed they gave a 40% power increase, now you are asking, would there be an advantage.

Ugh, all PowerCranks do is improve those areas. What I said is I can devise ways of emphasizing those areas, doing more than what occurs "naturally" with the PC's. In fact, many of my athletes already do something similar when they wear ankle weights out training. To emphasize the top or bottom all one need do is add resistance across the top or bottom during training and the change should eventually occur where it is seen in increased pedal force when the resistance is removed. Now, whether there is an advantage to such training (and how long would it take to see results) is unproven.

 

[coapman]

Ugh, all PowerCranks do is improve those areas. What I said is I can devise ways of emphasizing those areas, doing more than what occurs "naturally" with the PC's. In fact, many of my athletes already do something similar when they wear ankle weights out training. To emphasize the top or bottom all one need do is add resistance across the top or bottom during training and the change should eventually occur where it is seen in increased pedal force when the resistance is removed. Now, whether there is an advantage to such training (and how long would it take to see results) is unproven.

There would be no advantage because the muscles being used are not capable of producing effective crank torque. First you must accept the fact that there is only one dead spot sector, it's between 11-1 o'c, and with that taken care of, the lower one no longer exists. Without any additional training, yourself and coachfergie have muscles lying idle, which from day one are capable of applying the same max torque at 12 as the down force muscles apply at 3 o'c.

 

[CoachFergie]

There would be no advantage because the muscles being used are not capable of producing effective crank torque. First you must accept the fact that there is only one dead spot sector, it's between 11-1 o'c, and with that taken care of, the lower one no longer exists. Without any additional training, yourself and coachfergie have muscles lying idle, which from day one are capable of applying the same max torque at 12 as the down force muscles apply at 3 o'c.

You guys both have the most vivid imaginations.

 

[coapman]

You guys both have the most vivid imaginations.

What is your opinion on the dead spot sector(s) ?

 

[CoachFergie]

Outside of amusing myself with what people claim is important to cycling I focus on understanding the real demands of riding a bike, assessing the athletes preparedness and devising training methods to help them train.

 

[FrankDay]

There would be no advantage because the muscles being used are not capable of producing effective crank torque. First you must accept the fact that there is only one dead spot sector, it's between 11-1 o'c, and with that taken care of, the lower one no longer exists. Without any additional training, yourself and coachfergie have muscles lying idle, which from day one are capable of applying the same max torque at 12 as the down force muscles apply at 3 o'c.

I am not sure I have much of a clue what you are talking about. But, as long as your preferred pedaling technique does not involve any negative forces on the pedals at any time then it conforms to my definition of pedaling in circles. If it does involve any negative forces I look forward to hearing the rational as to how this helps the athlete.

 

[FrankDay]

You guys both have the most vivid imaginations.

I will take that over having no imagination.

 

[coapman]

I am not sure I have much of a clue what you are talking about. But, as long as your preferred pedaling technique does not involve any negative forces on the pedals at any time then it conforms to my definition of pedaling in circles. If it does involve any negative forces I look forward to hearing the rational as to how this helps the athlete.

Actually I can use any one of three techniques and for this special TT style I pedal in semi circles, all torque is applied between 11 and 5 o'c with no dead spot sector. One legged pedaling without counterweights cannot be used. This is a high gear technique which requires longer cranks in order to take full advantage of the additional maximal torque that is available between 11 and 2 o'c. There is probably slight negative force between 9 and 11 o'c but until I get to use Brimbros new powermeter I cannot be certain. If you have to ask how having the ability to apply maximal torque at 12, 1 and 2 o'c helps a cyclist, you have a problem I can't solve. Maybe you could explain where exactly in the pedaling circle PC's add that (20 - 40%) power increase or how PC pedaling differs from the ideal circular style.

 

[FrankDay]

If you have to ask how having the ability to apply maximal torque at 12, 1 and 2 o'c helps a cyclist, you have a problem I can't solve. Maybe you could explain where exactly in the pedaling circle PC's add that (20 - 40%) power increase or how PC pedaling differs from the ideal circular style.[/QUOTE]I didn't ask that question. The 40% improvement comes about because most people use, at most, about 35-40% of the pedaling circle to generate most of their power. It doesn't take much improvement in the remaining 60-65% to see substantial improvements. If a better technique exists I am anxious to see what it is (and the documentation that determines it is better) but until then I will accept the improvements we see from the modest changes we make in that "other" 65% of the pedal circle.

 

[FrankDay]

If you have to ask how having the ability to apply maximal torque at 12, 1 and 2 o'c helps a cyclist, you have a problem I can't solve. Maybe you could explain where exactly in the pedaling circle PC's add that (20 - 40%) power increase or how PC pedaling differs from the ideal circular style.

I didn't have any trouble with the bolded statement per se. Regarding PowerCranks, the 40% improvement comes about because most people use, at most, about 35-40% of the pedaling circle to generate most of their power. It doesn't take much improvement spread out over the remaining 60-65% to see substantial improvements overall. If a better technique exists I am anxious to see what it is (and the documentation that determines it is better) so I can figure out how to best train it but, until then, I will accept the improvements we see from the modest changes we make in that "other" 60-65% of the pedal circle.

 

[CoachFergie]

I didn't have any trouble with the bolded statement per se. Regarding PowerCranks, the 40% improvement comes about because most people use, at most, about 35-40% of the pedaling circle to generate most of their power. It doesn't take much improvement spread out over the remaining 60-65% to see substantial improvements overall. If a better technique exists I am anxious to see what it is (and the documentation that determines it is better) so I can figure out how to best train it but, until then, I will accept the improvements we see from the modest changes we make in that "other" 60-65% of the pedal circle.

Imagination = lying to yourself and others.

 

[coapman]

Regarding PowerCranks, the 40% improvement comes about because most people use, at most, about 35-40% of the pedaling circle to generate most of their power. It doesn't take much improvement spread out over the remaining 60-65% to see substantial improvements overall. If a better technique exists I am anxious to see what it is (and the documentation that determines it is better) so I can figure out how to best train it but, until then, I will accept the improvements we see from the modest changes we make in that "other" 60-65% of the pedal circle.

How do the objectives of a circular pedaler differ from those of a PC rider. Using the entire circle will improve performance but only when you are using circular hand cranks because the hand/arm muscles are capable of generating the same maximal force around the circle. You cannot get performance improvement by combining and merging minimal and maximal forces especially around the 9-3 o'c position because your brain will be attempting to balance these forces resulting in overall loss of torque from that of a masher. My special TT technique concentrates on generating constant maximal force from 11 to 5 o'c and merges forces from both legs for almost 360 deg of highly effective crank torque.

 

[Turner29]

I suggest everyone to get on a bike and apply force at the exact 12 o'clock position and see what happens.

 

[Turner29]

What is your opinion on the dead spot sector(s) ?

1) Applying force exactly at the 12 o'clock position generates no propulsive force.

2) Applying force during the 11 o'clock to 1 o'clock position generates very little propulsive force as most of the force is y-axis directed.

 

[FrankDay]

1) Applying force exactly at the 12 o'clock position generates no propulsive force.

2) Applying force during the 11 o'clock to 1 o'clock position generates very little propulsive force as most of the force is y-axis directed.

You should know or clarify what direction the force is being applied before you make such a blanket statement. It is also useful to know the magnitude of the force. Just because you may not do something doesn't mean others can't do it.

 

[coapman]

1) Applying force exactly at the 12 o'clock position generates no propulsive force.

2) Applying force during the 11 o'clock to 1 o'clock position generates very little propulsive force as most of the force is y-axis directed.

That's what engineers believed and wasted years of research trying to create equipment that could reduce the loss of power. The only equipment required to apply max torque at 12 is a pair of cleats and a brain that knows how to use them.

 

[Turner29]

That's what engineers believed and wasted years of research trying to create equipment that could reduce the loss of power. The only equipment required to apply max torque at 12 is a pair of cleats and a brain that knows how to use them.

Any force applied at 12 o'clock is transmitted directly down the crankshaft and into the bottom bracket and is 100% wasted.

Very easy to demonstrate.

 

[Turner29]

You should know or clarify what direction the force is being applied before you make such a blanket statement. It is also useful to know the magnitude of the force. Just because you may not do something doesn't mean others can't do it.

I am talking about basic physics that you don't seem to understand.

 

[coapman]

Any force applied at 12 o'clock is transmitted directly down the crankshaft and into the bottom bracket and is 100% wasted.

Very easy to demonstrate.

How about any torque applied at 12 o'c to which I was referring. ?

 

[FrankDay]

I am talking about basic physics that you don't seem to understand.

Really? You do understand the difference between force and torque don't you? Are you saying it is impossible to apply any torque at TDC? If so, how do you explain this actual data?

Note that they seem to be measuring a tangential force that would result in a torque (and, hence, power generation) at TDC.