Why pedal in circles?

Triathlon Forum
1

Here’s one that’s been nagging at me for awhile now.

Why is it so much better to pedal in circles? I know that it *is *better, but I don’t understand why. All I’ve ever read just says it’s more efficient. My question is, why is it more efficient? It seems counterintuitive, since you can apply so much more force on the downstroke than at the “deadspot.” Why doesn’t it work out to be more efficient to just concentrate on the area of the pedal stroke which is naturally more powerful?

The only thing I can think of is that it’s a momentum thing- like taking too much of a glide when swimming, losing forward momentum, and then having to get back to speed over and over again. But it seems like there must be more to it.

Any explanation is appreciated.

2

When you pedal in circles you are constantly using both of your legs and hip flexors as opposed to one leg at a time. It takes a while to learn the correct form but once you do you will notice less pain in the muscles you are now overworking. I was very stubborn for a long time and I only wanted to stomp down on the pedals, but when I finally did change, my legs felt much better during my run split.

3

Yeah, I realize it’s better, and all- not trying to make a case for mashing the downstroke by itself. Just looking for the why of it. Just doesn’t seem like the old hip flexors could really contribute all that much.

You know what might be interesting? Comparing bike times between a ride with clipless pedals, and a ride using plain platform pedals with no clips. Anyone have any data on something like that?

4

Studies show (IIRC) that the most powerful cyclists are the biggest “mashers”, which would suggest the whole pedaling circles idea is maybe not what really happens at the highest levels. Apparently there is little difference between efficiency of most cyclists, perhaps because the motion of pedalling a bike is so simple and constrained by the system (cranks) - it’s a lot different than running or swimming. Search out studies by Jim Martin or Andy Coggan for a better explanation.

Joel

5

Seriously. Ask the one-legged cyclist why it is better to pedal in circles.

If you used both of your legs as well as a one-legged cyclist uses one leg, pushing down as well as pulling up, you’ll be more efficient. The one-legged cyclist doesn’t go very far (unless he’s going downhill) unless he pulls up that crank for the next pedal stroke.

Look, there is no reason not to “mash” as much as your muscles and joints can take. Train those systems to their maximum. That’s where the BIG power comes from. But, now that you’ve generated all the power you can with these muscles, why waste any of this power to lift up the opposite leg, when you have muscles designed to do that?

Don’t try and make this more complicated with energy conservation theory, which muscles may or may not be “more efficient” and all that kind of clutter. Your cardiovascular system and your energy supply systems are very well equiped to deal with operating your hip flexors in sync and concomitantly with your extensor muscles.

Let me ask the opposite question, why in the world would you think it’s not better to recruit more muscle mass in order to ride faster/longer? This isn’t a fine motor control activity…

6

czone wrote: Studies show (IIRC) that the most powerful cyclists are the biggest “mashers”, which would suggest the whole pedaling circles idea is maybe not what really happens at the highest levels.

I don’t read those studies the same way. I read them to say that the top level cyclists in their study (how many were there, I forget, 8? 10?) did, indeed, tend to “mash” more than the second tier cyclists. But, it was noted that the second tier cyclists had some that pedalled in a “rounder” fashion, and that this allowed them to perform better than they would have if they were not pedaling “roundly”.

If you ride with others that are better than you, you will find that you begin to make adaptations to enable you to keep up. You’ll draft a little closer, things like that. Ever felt a cramping feeling up high in your calf on one of those rides? Like right where your hamstring muscle inserts? And maybe your hamstrings get tight and tired when they normally didn’t before? Guess what? You are being forced to recruit muscle you don’t normally use in order to ride a little faster. If you keep it up, you will use them more and more. If the guys you are chasing are only “mashers”, they will stay mashers, unless they ride with someone better than they are…THEN, they will find ways to be more efficient and/or produce more power, too. Their hamstrings will get tight, they’ll feel high calf pain, etc.

The human body does things in a lazy way…it finds how it can do something with as little effort as possible, unless it’s forced to do it otherwise. You may have to force yourself to learn to pedal in circles, but, you’ll be glad you did.

7

Anyone remember biopace chainrings from Shimano?

I got a pair of these last year for the heck of it…
In case you ahev never seen these these chain rings were ellipsoid / square looking. The idea was that the makimum torque was produced at the point whcih the pedal was the most powerful. This makes for a very unusual sensation of surging forward when going slower… very uncircular… (if such a word exists)

My udnerstanding of the circles thingy is that when you are riding for long periods of time (ie longer than a sprint)it is better to have a lower power output throughout the pedal stroke versus having a very high burst with a lull then another burst…
Kinda like a drag racer and a cadillac trying to race… over distance the drag racer is going to win… now if you are trying to go accross the US the cadillac is going to win becuase it can go for a longer time without gas, engine maintenance etc… I knwo bad analogy but the best i could come
up with on the spur…

Theory number 2: Chain rings are round… therefore pedalling should be “round”

Last comment: No imagine a person with perfect pedalling 100% efficient who can have a maximum force of 10 pounds… now compare that to someone with a 50% efficient but can produce 200 pounds of force well guess whose smoking who? Therefore pedalling efficiency only becomes useful when you are comparing people of equal “strength”

8

efficient spin is good, but man was not made to pedal in circles, he was made to walk up hills - pushing, and then to lift his leg up to the next step

this is why Rotor Cranks work so well, they take the already efficient human body and allow it to do what it does best - push

http://www.cyclingnews.com/tech.php?id=tech/2004/reviews/rotor_rs4
.

9

Because you’re recruiting more muscle groups. Better to divide the total workload amongst your hip flexors + quads and hamstrings than the latter 2 alone. Your LT is not limited on total cardiac output (assuming some training) but rather on the ability of muscle groups to use the available oxygen due to their capillary density, mitochondrial density, oxidative enzymes, etc. So the less more you can divide the workload the better.

Of course you can generate more force on the downstroke… but if you can generate a little less by unweighting your opposing leg you’ll help your main muscle groups and the metabolic cost of recruiting the hip flexors will be minimal.

10

“Of course you can generate more force on the downstroke… but if you can generate a little less by unweighting your opposing leg…”

You might care to note that “unweighting” is VERY different from “divide the total workload amongst your hip flexors + quads and hamstrings…” The whole controversy of spin v mash comes down to this difference.

From my reading of the literature, most studies seem to suggest that getting out of the way of the more powerful muscles (unweighting) is most efficient for the very highest level cyclists. At a certain point, trying to provide even torque around the full rotation of the crank interface does more to impede power output than increase it (due to the impossibility of both unweighting and providing torque from the same leg simultaneously.) The goal is to provide a more or less continuous power output from the 2 legs as a system, and the most efficient way to do this appears to be a dip in power output in one leg that corresponds to the peak power spike in the other leg (unweighting.) The theory of this is actually pretty easy to demonstrate graphically.

Powercrank Frank, by the way, doesn’t agree with this theory at all, and some of the Frank vs Coggan discussions on this topic have proven to be quite entertaining.

If you follow the competing theories to their logical conclusions, it is also apparent that you are either a fan of Power Cranks or of Rotor cranks - you can’t really do it both ways. Powercranks are specifically designed to train a physiological adaptation that is in direct opposition to the theory of the Rotor system. Training on Powercranks would promote maladaptation in terms of pedalling style for a user of the rotor system.

Interestingly, I have had the opportunity to ride extensively with one of the best one-legged cyclists in the world (he specializes in ultra-distance events, IE solo 24 hr. mtn bike racing and races such as the TransAlp Challenge - finishes mid pack in these!)

Note that he is a true one-legged cyclist, amputation above the knee. The way he pedals has very little to do with what would normally be considered “spinning.” When he is going slowly or at a low level of power output, he looks much like a two legged cyclist in terms of technique, but when high power output (especially in terms of torque) is required, he mashes, one legged. There is a clear surge-and-fade in his power output, and his position on the bike is very different from that of a two legged cyclist pedalling one legged; he orients his body in a way that would be essentialy impossible for a two legged cyclist -it looks much like an out of the saddle pedal stroke in a seated position - body orientation is slightly to the side of the bicycle (off center,) with a slight cant to the hips (if that makes any sense - again, graphic representation would be very helpful…)

How is this germane to the discussion? Trying to analyze cycling efficiency by looking at one leg is innappropriate. It’s only half the system. If you cut a V-8 engine in half, you don’t get a V-4. Even if one is to look at one leg’s motion on the crank in isolation, It may not be productive to make assumptions about ultimate efficiency as regards two legged cycling from this analysis. From my (admittedly very limited sample size) observations, the physical adaptation for cycling made by a one legged cyclist is very different from that of a 2 legged cyclist, and would be very inefficient, if not physically impossible, for a 2 legged cyclist to replicate as “half” of their pedal stroke.

MH

11

I disagree with a couple of things fredly said. There are engines that, when cut in half, do make a V-4 out of a V-8. They are called modular engines, and VW uses the concept in some of their newer products. They even bolt a V-4 module on the their V-8 to get a V-12.

Also, the point about the one-legged cyclist is this…UNLESS the cyclist pulls up enough to get the crankarm back up to the top, he only pedals one stroke. HE MUST pull up before making the next stroke. The one-legged rider that contorts his position to get better extensor power is an example of trying to maximize conditions to favor his use of extensors…that’s great…that is what Rotorcranks do…adjust the pedal stroke so that there is an increase in extensor power. Still, unless and until the one-legged rider PULLS UP to get the rising crank over the top, he’s stuck with one pedal stroke only. While THIS IS MORE EFFICIENT for a two legged rider, it is absolutely imperative for a one-legged rider.

I also don’t think Rotorcranks and PowerCranks are opposites, like Science vs. Creation Theory. Rotorcranks attempt (apparently successfully, I might add) to take advantage of the bigger, better adapted pushing muscles. PowerCranks attempt (successfully) to teach one to at least unweight the rising crank system…just like the one-legged rider MUST do. There may also be a possibility that one can train the hip flexors to add power to the pedal stroke…I don’t really know…it certainly seems possible. BUT, pulling up doesn’t detract from pushing down with the contra-lateral leg. This is an additive force.

Rotorcranks and PowerCranks are NOT opposites…as long as one has trained on one system long enough to derive benefits from it, there would be an additive benefit to training on the other system…Rotors reportedly increase the efficiency of the extensors, but Rotors still use extensor power to lift the rising leg. A PowerCrank trained rider that has also adapted to Rotors, would be even better than a Rotor-only rider. Rotors and PowerCranks would be like the people that believe in Creation, with Evolutionary changes that followed the initial creation…they aren’t opposites, indeed, they are complimentary.

One other consideration, though, is that PowerCranks help run speed. Across the board, fairly quickly. I have never heard of anyone that didn’t run better after training on PowerCranks. I talked to a coach of hundreds of athletes, and each and every one of his PowerCranked trained athletes run faster, and it doesn’t take long before this happens…weeks. His non-PowerCrankers don’t have the same run improvements. Rotors haven’t been shown to do anything to increase run speed. I’d like to have both systems. But, as a triathlete that must run off the bike, if I only had one, it would be PowerCranks.

Something I really did agree with fredly on, was not trying to compare a pedal stroke that is even torqued all around with a mashing down only stroke. Extensors generate more force than flexors in the normal human…no reason to suggest otherwise (although, this doesn’t mean that there isn’t untapped potential from training the flexors to do more than “normal”). The goal isn’t to equalize the power around the entire pedal stroke, the goal is to at least remove the inefficiency of using pushing down muscles to raise something (the rising leg system) that we could use other muscles (hip flexors) to perform…freeing up this pushing down force to now go to the chain.

12

I think I now understand how both systems work. Rotor Cranks spread the workload that your extensors do over a greater “arc” of the pedal stroke, thus reducing the peak force required during each stroke. This would explain why RC users generate less lactic acid at the same power output, they dont need to push quite as hard, thus not requiring use of anaerobic mechanisms to the same degree. Power Cranks train you to lift the trailing leg, the goal being to avoid wasting your extensor energy lifting that leg.

I agree that they are not mutually exclusive systems. I am waiting for more scientifically sound studies to prove that the systems work before I think about laying down some of my hard earned cash on anything.

As an interesting aside, testing indicates that elite mountain bikers had a more symmetrical pedal stroke than their road riding counterparts. This is probably due to the requirements of maintaining traction on slippery terrain. Try riding a rigid singlespeed uphill to learn how to maintain a smooth pedal stroke.

13

I think a reason that circles are better is that it evens out the power application. Even while going a constant speed, the bike is moving in a slight cycle of accelerating and decelerating. A circular pedal stroke reduces the variations. I think this is also part of the reason why reducing rotating weight such as wheels gives better returns than static weight. I think your swimming analogy is good.

14

"Also, the point about the one-legged cyclist is this…UNLESS the cyclist pulls up enough to get the crankarm back up to the top, he only pedals one stroke. HE MUST pull up before making the next stroke. The one-legged rider that contorts his position to get better extensor power is an example of trying to maximize conditions to favor his use of extensors…that’s great…that is what Rotorcranks do…adjust the pedal stroke so that there is an increase in extensor power. Still, unless and until the one-legged rider PULLS UP to get the rising crank over the top, he’s stuck with one pedal stroke only. While THIS IS MORE EFFICIENT for a two legged rider, it is absolutely imperative for a one-legged rider. "

Why is this more efficient for the 2 legged cyclist?

“PowerCranks attempt (successfully) to teach one to at least unweight the rising crank system”

No, they don’t. Unweighting is a different adaptation from pulling through with the hip flexors - that’s the selling point of PowerCranks

“BUT, pulling up doesn’t detract from pushing down with the contra-lateral leg. This is an additive force.”

No, it’s not. If th contra-lateral leg is impeded in it’s max torque phase by the other leg, you don’t gain power. The question is whether or not this happens, and I think it does…

"Rotors reportedly increase the efficiency of the extensors, but Rotors still use extensor power to lift the rising leg. A PowerCrank trained rider that has also adapted to Rotors, would be even better than a Rotor-only rider. Rotors and PowerCranks would be like the people that believe in Creation, with Evolutionary changes that followed the initial creation…they aren’t opposites, indeed, they are complimentary. "

PowerCrank adaptation is specific to Powercranks, and teaches the rider to pull through the top of the pedal stroke (using flexor motion), which is NOT complimentary to Rotors. You’re missing the point. You can’t use power to lift the rising leg AND unweight the rising leg - these are different physiological adaptations. Either you believe the PowerCranks theory of even torque distribution for each leg, or you believ the Rotor theory of maximizing extensor output. Rotors play with the lever arm of the linkage system in the Human/bike interfac in a way that maximizes the duration and output of the extensor phase of the pedal stroke for each leg. You could design a Rotor-like system to enhance flexor efficiency, creating a more even torque band for each leg, but this would be a very different device -and why would you want to do that, Extensor motion being so much more efficient? It wouldn’t make any sense…

Creationism…? Yikes…

I do believe that PowerCranks help with running speed, note this is VERY different physiologically from cycling (I believe, by the way, that this is evidence to support my other conclusions…)

"Something I really did agree with fredly on, was not trying to compare a pedal stroke that is even torqued all around with a mashing down only stroke. Extensors generate more force than flexors in the normal human…no reason to suggest otherwise (although, this doesn’t mean that there isn’t untapped potential from training the flexors to do more than “normal”). The goal isn’t to equalize the power around the entire pedal stroke, the goal is to at least remove the inefficiency of using pushing down muscles to raise something (the rising leg system) that we could use other muscles (hip flexors) to perform…freeing up this pushing down force to now go to the chain. "

There is no efficiency loss from using the pushing down muscles to raise the off side crank if you look at the torque figures for the human/crank interface as a whole. It is more efficient to use the extensors than to use the flexors, because attempting to train the flexors results in an adaptation that impedes the extensors max output, especially at high cadences. The goal is to get the highest average wattage for the totality of the output curve, not just for the single leg. As has been mentioned previously, if you look at the torque curves for elite track riders, the curve is markedly uneven for each leg, with huge power coming from the extensor phase and very little from the flexor. If you go a step further, and map torque across both legs, you see that the power spike of one leg corresponds with the power drop of th other, and the output as a whole is fairly evenly distributed across a (2 leg) cycle/phase. These riders can’t add power to their stroke by utilizing flexor motion, rather the torque figures show a rapid unweighting (or drop in torque.) The riders have developed an adaptation that can be summarised as getting the flexor leg out of the way as quickly as possible so that the leg currently in extensor mode can operate unimpeded.

It is interesting to note that the most even torque curves tend to come from mountain bike athletes; the adaptation these athletes make is different from that of road/track cyclists. Power output in mountain biking is highly dependant on traction, so the power curve tends to be smoother, although of a lower overall /average wattage. Contrast this with the aforementioned track riders, and realize that road cyclists are somewhere in the middle, and a pattern begins to emerge.

MH

15

Vitus, like any force, there is a magnitude component and a directional component. No one is saying to not push down hard. Just ensure that the force is always applied 90 degrees to the crank (tangential to the crank, so along the direction of the circle), and there is alsways some positive force on the crank. By all means, hammer down with your quads as hard as you can, but also pull around with your hamstrings, lift with your hip flexors and slightly kick forward over the top before hammering down again. The worst this you can do is reduce the force on the powerful downstroke and try to bring the upstroke to a magnitude equivalent to the downstroke. It will never happen. Work your strengths, and minimize your weaknesses, but don’t sacrifice your strengths while improving your weaknesses. Hope this helps.

By the way, I am a powercrank rider and I do agree with Gary Tingley of Rotorcranks thaht man was made to push down with the quads. This is why I say to hammer down with the quads. But I do agree with the others that working all muscles involved in positive application of force through the pedal stroke can only offer overall benefits.

16

mad aussie wrote: I think I now understand how both systems work. Rotor Cranks spread the workload that your extensors do over a greater “arc” of the pedal stroke, thus reducing the peak force required during each stroke. This would explain why RC users generate less lactic acid at the same power output, they dont need to push quite as hard, thus not requiring use of anaerobic mechanisms to the same degree. Power Cranks train you to lift the trailing leg, the goal being to avoid wasting your extensor energy lifting that leg.

See? Someone else said the same thing I’ve been trying to say, just with 1000 less words. The only thing I’d add, is to say PC’s “at least” train you to lift the trailing leg…they may allow more than that…

17

fredly wrote: Unweighting is a different adaptation from pulling through with the hip flexors.

I disagree, pulling through with the hip flexors is an adaptation in excess of simply unweighting.

fredly wrote: If the contra-lateral leg is impeded in it’s max torque phase by the other leg, you don’t gain power.

I agree. However, I do not agree that the contra-lateral leg is impeded in it’s max torque phase by the other leg. Furthermore, if you push down hard enough, you will rise from the seat, unless you pull down with your arms…which are connected to your back and hips…OR, you can pull up with the contra-lateral leg in order to stay seated. Either way, you have to counter a BIG push with some other force if the big push exceeds the shear weight of your body.

Fredly: You’re missing the point. You can’t use power to lift the rising leg AND unweight the rising leg - these are different physiological adaptations. Either you believe the PowerCranks theory of even torque distribution for each leg, or you believ the Rotor theory of maximizing extensor output.

I don’t think you understand this the way I do. You CAN lift barely enough to just raise the rising leg to match the speed of your downward pushing leg, or, you can lift more than enough to match the speed, either way, you are eliminating any wasted energy being produced by the pushing leg…in the latter case, you are actually contributing forces which will end up in the chain…where it counts. Again, Rotors and PC’s are not mutually exclusive.

Fredly: There is no efficiency loss from using the pushing down muscles to raise the off side crank if you look at the torque figures for the human/crank interface as a whole. It is more efficient to use the extensors than to use the flexors, because attempting to train the flexors results in an adaptation that impedes the extensors max output, especially at high cadences.

I used to have a VERY smooth pedal stroke…before PC’s. Torquer figures can fool you. Jim, at Right Gear in Concord, NC, one of George Hincapie’s old sources of bike-related performance technique and info, as well as Chris Harkey and darn, I can’t remember the other Time Trialist specialists name at the moment, well, Jim told me during a fitting that I had a pedal stroke that was as good as the 95th percentile of all the athletes he’s seen. Since training on PC’s, my pedal stroke is much more surging…because it turns out I was artificially turning a smooth stroke by attenuating a very power push with resistance by my rising leg. Now that I no long have that resistance from my rising leg, my pedal stroke isn’t as smooth, but, with no wasted power from my extensors being used up to raise the contra-lateral leg, my power at the wheel is a good bit higher, and I am faster. As far as extensors being inhibited by flexors at high rpm’s…maybe, but at rpm’s that aren’t practical in time trials by virtue of their sheer inefficiency. Every motion produced by a limb contains a bit of inefficiency…using the limb more times per minute produces more inefficiency per minute. Time trialists typically don’t run NEARLY high enough cadences for this inhibitory effect to occur.

Fredly: Why is this (picking up the rising leg) more efficient for the 2 legged cyclist?

Tell me why it possibly isn’t. Ridding oneself of resistance by lifting the rising leg simply doesn’t waste power generated by the extensors.

You really must ride on PowerCranks to see what it’s all about. Apparently, my feeble attempts at talking about them misses something in the translation.

Again, I think Rotors and PC’s are different, but complementary…you CAN benefit from each.

BTW, I have NO connection with either device, but, I do have experience with PC’s.

19

I consciously tried to be a very smooth pedaller, I worked on it a lot. However, now, I don’t care as long as I get my rising leg out of the way, so I’m not wasting pushing forces generated by the other leg, forces that now go to the crank.

As far as inhibitory effects, certainly, extensors can fire just prior to TDC…to use an automotive term…just as a spark in a cylinder of an engine fires before TDC. I was speaking about inhibitory effects that were designed by nature, or God, depending upon your viewpoint, that protect a joint from excessive forces, the inhibitory pathways that prevent maximal contraction of opposing muscle groups. I think it’s fine to have inhibition of maximal hip flexor muscle, as well as extensor, if it does indeed occur at these usable rpms, simply because a time trial doesn’t require anywhere near maximal forces of these muscles. A sprint at high rpm is a different animal…you probably have to push down as hard as you can without regard to “efficiency”, as long as you are generating power at the wheel. Sprinting and time trialing aren’t similar in my book. I was a very good sprinter, not a good time trialer. Now, I don’t sprint any more, but, I have a decent time trial…for an old man…I’m faster on a time trial now that my age is closer to 50 than when I was in my mid 20’s.

21

Let me ask the opposite question, why in the world would you think it’s not better to recruit more muscle mass in order to ride faster/longer?

I don’t- I accept completely the circle dogma. I’m trying to get a good explanation of “how” it works, that’s all.

Thanks to all for the replies, which were, as usual, quite helpful.

Sifting, sifting. . .

22

I’ve heard of the Laws of Thermodynamics and fail to see where they fit here. Please humour me and explain. Are you talking about the 1st law? The 2nd? I’m lost…