What I was trying to get at is, if one takes into account the effects of gravity then it is easily shown that those who do not put any faith in “pedaling in circles” because of what pedal forces show so they see no need to train new muscles will find out they are using those muscles anyhow. The only question then becomes, is there any benefit to training those muscles a little more than they are now.
FWIW, Jeff doesn’t think so.
I disagree with a lot of what they say. Their argument would fall apart if they had done the energy analysis at several different cadences. That being said, I think this is a pretty much worthless paper for this debate. Has nothing to do with what Broker said.
On the contrary: this was specifically the line of reasoning to which Broker was alluding.
“” Understanding those non-muscular effects could prevent a coach from engaging in a counter-productive effort of trying to encourage a rider to eliminate forces which actually come at no energy cost. Indeed, the effort to eliminate them can actually cost a rider energy and efficiency."
i believe this is what AC was referring to. in this instance it does apear the man is trying to say that the " scrape the poo off the shoe " technique might be counterproductive. which, in some circumstances it may well be. there is some merit in pointing out some coaches make too big a deal about that.
it has little or nothing to do with powercrank style riding, as i see it.
it is not really all that earth-shattering from the standpoint of claiming that standing still on a leg is a low-energy thing to do. indeed, if you think of standing climbing you stand nearly still on your leg at the bottom of the pedal stroke every revolution as a bit of a rest.
none of the assertions take into account any of the other styles of pedalling a rider uses . . . such as light-pedalling in a tailwind or draft, or after a gruelling climb, etc. the article appears to a snapshot of a predominantly academic overworded bit of info most people already knew anyway.
I don’t believe that teaching someone to “scrape the poo off the shoe” is an attempt to “encourage a rider to eliminate forces which actually come at no energy cost.” A horizontal force backwards does nothing to reduce the downward force of gravity and would only add propulsive force at this point in the stroke. Adding propulsive force in order to go faster is the goal isn’t it?
Yo can see this in action when you remove one pedal from the crankset, the other pedal naturally wants to drop to the 6 o’clock position – with it’s own gravitational force. In other words, gravity takes the pedal down to the bottom. It’s a crude comparison but is this what broker is talking about? That the downstroke comes naturally and we should not expend energy trying to alter/eliminate it?
~ AB ~
I disagree with a lot of what they say. Their argument would fall apart if they had done the energy analysis at several different cadences. That being said, I think this is a pretty much worthless paper for this debate. Has nothing to do with what Broker said.
On the contrary: this was specifically the line of reasoning to which Broker was alluding.
Boy, you could have fooled me. I saw this as a discussion of internal vs external work. Exactly where in the paper are they talking about not trying to eliminate forces caused by gravity at the bottom of the stroke, or did I misinterpret what Broker said also? If so, exactly what is Broker trying to say?
I disagree with a lot of what they say. Their argument would fall apart if they had done the energy analysis at several different cadences. That being said, I think this is a pretty much worthless paper for this debate. Has nothing to do with what Broker said.
On the contrary: this was specifically the line of reasoning to which Broker was alluding.
Boy, you could have fooled me. I saw this as a discussion of internal vs external work. Exactly where in the paper are they talking about not trying to eliminate forces caused by gravity at the bottom of the stroke, or did I misinterpret what Broker said also? If so, exactly what is Broker trying to say?
He’s saying “don’t fight Mother Nature”. 
He’s saying “don’t fight Mother Nature”.
No he isn’t. He is saying, I interpret mother nature differently than all you other guys. Here is the “proper” energy analysis (at least according to him).
His analysis doesn’t mention gravity. Broker’s analysis was all about gravity.
He’s saying “don’t fight Mother Nature”.
No he isn’t. He is saying, I interpret mother nature differently than all you other guys. Here is the “proper” energy analysis (at least according to him).
His analysis doesn’t mention gravity. Broker’s analysis was all about gravity.
You need to read Kautz’s paper more carefully. While he may not mention gravity, his analyses most certainly take it into account (as do numerous other studies, i.e., this is not anything particularly new).
Yo can see this in action when you remove one pedal from the crankset, the other pedal naturally wants to drop to the 6 o’clock position – with it’s own gravitational force. In other words, gravity takes the pedal down to the bottom. It’s a crude comparison but is this what broker is talking about? That the downstroke comes naturally and we should not expend energy trying to alter/eliminate it?
~ AB ~
Essentially, yes. That is, he’s saying that you need to separate the gravitational, inertial, and muscular forces to really understand what is going on, and that it is energetically costly to work too hard trying to redirect the total force (and thus, e.g., produce a prettier SpinScan).
He’s saying “don’t fight Mother Nature”.
No he isn’t. He is saying, I interpret mother nature differently than all you other guys. Here is the “proper” energy analysis (at least according to him).
His analysis doesn’t mention gravity. Broker’s analysis was all about gravity.
You need to read Kautz’s paper more carefully. While he may not mention gravity, his analyses most certainly take it into account (as do numerous other studies, i.e., this is not anything particularly new).
He does mention gravity because he refers to the potential energy in the leg around the pedal stroke. But, he is doing so to try to differential between internal and external work. His analysis would be the same if he were doing this analysis in space where there is no gravity (so no variation in potential energy). If his analysis would not be the same in these two environments then his analysis is flawed. His analysis does not depend upon gravity so it cannot be related to what Broker is talking about.
His analysis does not depend upon gravity so it cannot be related to what Broker is talking about.
You must have missed these parts (under “Consequences for Pedaling Biomechanics”)
"Effective” crank force is a misnomer
Studies have also sought to explain differences in the cost
of pedaling with the concept of more “effective” crank force generation (e.g., (11)). The tangential crank force is the only component that directly acts to propel the crank and contributes to external work, and the terms “effective” and “ineffective” have been used to describe pedal forces that are oriented tangential and radial to the crank (Fig. 6), respectively. However, it is erroneous to conclude that the radial component should be minimized to decrease energy expenditure or cycle faster because a significant amount of the radial component results from nonmuscular (i.e., gravity, coriolis, and centripetal forces) contributions (7). In addition, our demonstration above that the pedal force is dominated by energy transferred to the crank by the plantar flexors reveals that the muscular contributions to the crank force are likely to have significant radial components as well. Specifically, the orientation of the pedal force due to the plantar flexors at any instant in the crank cycle is uniquely determined by geometry of the leg, with changes in the magnitude of muscle excitation merely changing the magnitude of this pedal force. Thus, there is a limited ability to control the orientation of this crank force. As a result, the net action of muscles will almost assuredly produce a radial component of the crank force and eliminating it would require the recruitment of additional muscles to offset the radial component, causing the metabolic cost to go up." ***** Negative crank power during the upstroke does not imply additional mechanical cost * Previous work has partially refuted this misconception by showing that more muscular effort would be required to eliminate the negative torque (counter-torque) during the upstroke than would be required to pedal normally with a counter-torque (13). Note that the counter-torque represents work done on the upstroke leg, not necessarily that the leg is pushing down. In fact, during the upstroke muscles do significant positive work (e.g., Fig. 4, all other muscles) and little negative work. Most of this negative work would still exist even if counter-torque were eliminated by other concentric muscles (e.g., hip flexors) because it is associated with the deactivation of muscles such as VAS (Fig. 4). Because little dissipation of energy by negative muscle work occurs, the work associated with the counter-torque results in increased energy of the leg as the potential and kinetic energies increase as the leg is pushed upwards (Fig. 2B and 2D). Thus, counter-torque can simply represent the transfer of energy from the downstroke leg to the upstroke leg."
Thinking about this realistically, the leg wants to fall down naturally (on its own weight) on the downstroke and it would take energy to deviate from this naturally occuring process. After all, the leg acts as a large and heavy counterweight - much like the single pedal on the crankset example. I haven’t done this but would you need to considerably unweight the downstroke to have a pretty/evenly distributed spinscan?
~ AB ~
Yo can see this in action when you remove one pedal from the crankset, the other pedal naturally wants to drop to the 6 o’clock position – with it’s own gravitational force. In other words, gravity takes the pedal down to the bottom. It’s a crude comparison but is this what broker is talking about? That the downstroke comes naturally and we should not expend energy trying to alter/eliminate it?
~ AB ~
Essentially, yes. That is, he’s saying that you need to separate the gravitational, inertial, and muscular forces to really understand what is going on, and that it is energetically costly to work too hard trying to redirect the total force (and thus, e.g., produce a prettier SpinScan).
If the downstroke comes so naturally, why do we bother pushing? Of course, riding a bike is energetically costly, especially if we want to go fast. The question is, if redirecting forces makes one go faster or more efficiently (or both) then there is a reason for putting the effort into making those changes. An example would be to make the forces already there more tangential. If redirecting the forces does not make the bike go faster (minimizing the downward force at the 6 o’clock position) then the effort is wasted.
They do when they are coasting (resting) with both legs down, but I suspect they don’t when they are riding because they have to be pulling back which means the hamstrings are activated and the reactive force would tend to push the knee up some, reducing the downward force due to the dead weight of the leg on the pedal at the 6 o’clock position. I suspect the same is true for most riders who are trying to scrap the poo off the shoe. In addition, the PC’er is probably anticipating the upstroke some which would also tend to unweight the pedal some.
Frank
I was expecting that answer, which was why I could not understand how you could be in agreement with J. Broker. I notice there is no mention of what the upper 12 o’c pedal is supposed to be doing. Anquetil never had to worry about his 6 o’c pedal because at that stage his total concentration was on max power application to the 12 o’c pedal with his special linear pedaling technique which is and always has been beyond the comprehension of all pedaling scientists who appear to be mentally limited to repetitive analysis of variations of the same old natural pedaling style.
They do when they are coasting (resting) with both legs down, but I suspect they don’t when they are riding because they have to be pulling back which means the hamstrings are activated and the reactive force would tend to push the knee up some, reducing the downward force due to the dead weight of the leg on the pedal at the 6 o’clock position. I suspect the same is true for most riders who are trying to scrap the poo off the shoe. In addition, the PC’er is probably anticipating the upstroke some which would also tend to unweight the pedal some.
Frank
I was expecting that answer, which was why I could not understand how you could be in agreement with J. Broker. I notice there is no mention of what the upper 12 o’c pedal is supposed to be doing. Anquetil never had to worry about his 6 o’c pedal because at that stage his total concentration was on max power application to the 12 o’c pedal with his special linear pedaling technique which is and always has been beyond the comprehension of all pedaling scientists who appear to be mentally limited to repetitive analysis of variations of the same old natural pedaling style.
I was only in agreement with Broker in that he has analyzed the contribution of gravity to the forces applied to the pedal. If one does this it will soon become obvious that everyone unweights on the upstroke, what is commonly referred to as pedaling in circles, with the only difference being the degree (and, perhaps, the direction) with which they do so.
There are only so many things that one can do with their feet on the pedals of a bicycle and make it go forward with any degree of efficiency. Even Anquetil would be doing one of these variations. The differences in these variations will be subtle in trained cyclists, in most instances. Although subtle, these differences can result in substantial power and efficiency differences.
There are only so many things that one can do with their feet on the pedals of a bicycle and make it go forward with any degree of efficiency.
Correct.
Even Anquetil would be doing one of these variations. The differences in these variations will be subtle in trained cyclists, in most instances. Although subtle, these differences can result in substantial power and efficiency differences.
Incorrect (as evidenced by the fact that there is a close correlation between fiber type and cycling efficiency…this would not be true if biomechanical factors played a significant role.)
His analysis does not depend upon gravity so it cannot be related to what Broker is talking about.
You must have missed these parts (under “Consequences for Pedaling Biomechanics”)
"Effective” crank force is a misnomer
Studies have also sought to explain differences in the cost
of pedaling with the concept of more “effective” crank force generation (e.g., (11)). The tangential crank force is the only component that directly acts to propel the crank and contributes to external work, and the terms “effective” and “ineffective” have been used to describe pedal forces that are oriented tangential and radial to the crank (Fig. 6), respectively. However, it is erroneous to conclude that the radial component should be minimized to decrease energy expenditure or cycle faster because a significant amount of the radial component results from nonmuscular (i.e., gravity, coriolis, and centripetal forces) contributions (7). In addition, our demonstration above that the pedal force is dominated by energy transferred to the crank by the plantar flexors reveals that the muscular contributions to the crank force are likely to have significant radial components as well. Specifically, the orientation of the pedal force due to the plantar flexors at any instant in the crank cycle is uniquely determined by geometry of the leg, with changes in the magnitude of muscle excitation merely changing the magnitude of this pedal force. Thus, there is a limited ability to control the orientation of this crank force. As a result, the net action of muscles will almost assuredly produce a radial component of the crank force and eliminating it would require the recruitment of additional muscles to offset the radial component, causing the metabolic cost to go up." ***** Negative crank power during the upstroke does not imply additional mechanical cost * Previous work has partially refuted this misconception by showing that more muscular effort would be required to eliminate the negative torque (counter-torque) during the upstroke than would be required to pedal normally with a counter-torque (13). Note that the counter-torque represents work done on the upstroke leg, not necessarily that the leg is pushing down. In fact, during the upstroke muscles do significant positive work (e.g., Fig. 4, all other muscles) and little negative work. Most of this negative work would still exist even if counter-torque were eliminated by other concentric muscles (e.g., hip flexors) because it is associated with the deactivation of muscles such as VAS (Fig. 4). Because little dissipation of energy by negative muscle work occurs, the work associated with the counter-torque results in increased energy of the leg as the potential and kinetic energies increase as the leg is pushed upwards (Fig. 2B and 2D). Thus, counter-torque can simply represent the transfer of energy from the downstroke leg to the upstroke leg."
This paper is putting forth an alternative energy analysis of pedaling over what others have theorized. It is not proven or anything else. Everything he is saying here is hypothetical as far as I can see. I suspect few whose ideas he has criticized here have hopped onboard this hypothesis as being clearly superior to their own analysis.
Anyhow, it is clearly fallacious to say “it is erroneous to conclude that the radial component should be minimized to decrease energy expenditure or cycle faster because a significant amount of the radial component results from nonmuscular (i.e., gravity, coriolis, and centripetal forces) contributions (7).” It is only erroneous to conclude such when in fact such forces result from nonmuscular contributions. But, in fact, most radial components of the pedal force are most likely do to muscular forces inartfully applied. the fact that some radial forces may come from non-muscular sources does not negate this fact. In this instance, there is much to be gained from reducing the part of this component from poorly applied muscular forces.
What do they say about this: “the net action of** muscles will almost assuredly produce a radial component of the crank force and eliminating it would require the recruitment of additional muscles to offset the radial component, causing the metabolic cost to go up.**” Such utter hogwash. Depending upon the forces and orientation of the crank it is just as likely that “eliminating” the radial component could just as easily come from reducing the firing of certain muscles as opposed to needing to recruit new ones. Using fewer muscles for the same benefit would clearly be an advantage it would seem.
At least this paper agrees with my point here: “In fact, during the upstroke muscles do significant positive work (e.g., Fig. 4, all other muscles) and little negative work.” Thanks for pointing that out.
Incorrect (as evidenced by the fact that there is a close correlation between fiber type and cycling efficiency…this would not be true if biomechanical factors played a significant role.)
and you’re using as your evidence for this the Coyle study of Lance Armstong where he showed that Lance increased his pedaling efficiency substantially over this period so it was hypothesized that this could have only come from Lance changing his fibre type in his legs (even though no biopsy was obtained to support the hypothesis)? Or, the Luttrell study which showed a 10% increase in cycling efficiency in 6 weeks, presumably from changing pedaling technique (biomechanical factors?), of training with PowerCranks. Oh, wait, the Luttrell study doesn’t make your point. And, neither does the Coyle study.
You are basing your bias on old data. Unless it were possible to actually change cycling technique then it was not possible to study and analyze the benefits or lack of benefits of different techniques. Until PowerCranks there was no reliable way of actually changing pedaling technique so these old wives tales that technique doesn’t matter came to be.
Me thinks you are reading too much into these old papers. We will see how long you hang on to this old way of thinking. The times they are a changing.
Since this started with Broker, how about Joe Lindsay’s report of Broker’s suggestion “that he’d also gotten results by telling riders to visualize pedaling “horizontally” rather than in circles” and that “Isolated leg training may also help”? (By “gotten results” I presume Lindsay meant “good results”.)
There are only so many things that one can do with their feet on the pedals of a bicycle and make it go forward with any degree of efficiency. Even Anquetil would be doing one of these variations.
With that first sentence you fall into the same trap as all the other researchers, why limit it to the lower body and the feet. No, Anquetil did not use one of those variations, all of them use vertical pedal pressure as main power supplier, Anquetil never used vertical pedal pressure.