Oval chainrings are back?

[dnc]

Originally Posted by martl

Torque is the least significant thing that would need improving, because of a moving bike's inertia. The same goes for the so-called "dead spot" at the 12 o'clock position.

It also is a myth that that improving "pedalling efficiency" would cause an effect on riding performance.

Physiological Responses during Cycling With Oval Chainrings (Q-Ring) and Circular Chainrings. (Cordova A1, Latasa I2, Seco J3, Villa G4, Rodriguez-Falces J2.)

"During the incremental exercise test, no significant differences were found in power output, oxygen consumption or heart rate between oval "Q-rings" and conventional chainrings.Over the course of the incremental test, blood lactate levels were comparable for the oval "Q-rings" and conventional chainrings.During the short sprints performed after the incremental test, there were no statistical differences in power production between oval "Q-rings" and conventional chainrings."


"Cycling efficiency is related to the percentage of Type I muscle fibers" (EDWARD F. COYLE, LABROS S. SIDOSSIS, JEFFREY F. HOROWITZ, and JOHN D. BELTZ)

"We previously observed that cycling economy (i.e., W.I-1 VOz.min-l; seeTable 3 of ref. 5) can vary greatly in a group of well-trained cyclists. It was clear, however, that these differences in cycling economy were not due to differences in cycling technique, evidenced by various biomechanical data derived from the use of an instrumented pedal dynamometer (5)."

Scientists have a lot to learn about pedalling, in the natural pedalling technique the strongest muscle in the lower body which can have up to 100 % type 1 (slowtwitch) muscle fibers is left lying idle. With a change in technique it can replace that entire sector between 11 and 2 o'c with close to maximal torque.
Most recent scientific research claims attempts to use this muscle would result in negative torque ? What cyclists and scientists call different techniques are nothing more than variations of the same basic technique where most torque is applied between 2-4 o'c.

[martl]

Originally Posted by dnc

Scientists have a lot to learn about pedalling, in the natural pedalling technique the strongest muscle in the lower body which can have up to 100 % type 1 (slowtwitch) muscle fibers is left lying idle. With a change in technique it can replace that entire sector between 11 and 2 o'c with close to maximal torque.

You dont name the muscle. Which one would that be?

Most recent scientific research claims attempts to use this muscle would result in negative torque ? What cyclists and scientists call different techniques are nothing more than variations of the same basic technique where most torque is applied between 2-4 o'c.

What benefit does a rider in motion gain from more *torque*?

[berserk87]

Good responses all.

Had a good friend that rode oval rings for a couple of years. He couldn't tell any difference between them and round rings, other than the shifting on the ovals was tougher to manage.

Seems like snake oil to me but there's nothing to indicate that they are harmful, if you believe in them.

The false-cause fallacy that 5 out of the past 7 TDF winners have ridden them probably doesn't hurt sales.

[dnc]

Originally Posted by martl

You dont name the muscle. Which one would that be?


What benefit does a rider in motion gain from more *torque*?

Soleus muscle

" Function

The action of the calf muscles, including the soleus, is plantarflexion of the foot (that is, they increase the angle between the foot and the leg). They are powerful muscles and are vital in walking, running, and keeping balance. The soleus specifically plays an important role in maintaining standing posture; if not for its constant pull, the body would fall forward.

Also, in upright posture, the soleus is responsible for pumping venous blood back into the heart from the periphery, and is often called the skeletal-muscle pump, peripheral heart or the sural (tricipital) pump.

Soleus muscles have a higher proportion of slow muscle fibers than many other muscles. In some animals, such as the guinea pig and cat, soleus consists of 100% slow muscle fibers. Human soleus fiber composition is quite variable, containing between 60 and 100% slow fibers.

The soleus is the most effective muscle for plantarflexion in a bent knee position. This is because the gastrocnemius originates on the femur, so bending the leg limits its effective tension. During regular movement (i.e., walking) the soleus is the primary muscle utilized for plantarflexion due to the slowtwitch fibers resisting fatigue. "

The more torque (force applied at a right angle to the crank) a rider can apply to his cranks with the mashing technique, the faster he will go in a sprint, but that's not the most effective way to produce sustainable torque for time trials, for that you need the most fatigue resistant muscle like the soleus.
The objective of all these non round shaped chainrings is to try and compensate for the inability of riders to apply effective torque around TDC by prolonging time spent in the 2-4 o'c sector where most effective torque can be applied, but you don't have sufficient time to make the necessary adjustments to your pedalling that will give you this advantage (if any).

[makoti]

Originally Posted by berserk87

The false-cause fallacy that 5 out of the past 7 TDF winners have ridden them probably doesn't hurt sales.

Someone once said "It's the motor". That doesn't sell many new parts, though.

[Mark McM]

Originally Posted by dnc

Scientists have a lot to learn about pedalling, in the natural pedalling technique the strongest muscle in the lower body which can have up to 100 % type 1 (slowtwitch) muscle fibers is left lying idle. With a change in technique it can replace that entire sector between 11 and 2 o'c with close to maximal torque.
Most recent scientific research claims attempts to use this muscle would result in negative torque ? What cyclists and scientists call different techniques are nothing more than variations of the same basic technique where most torque is applied between 2-4 o'c.

If applying maximum torque through the pedal stroke was the key to maximizing power, than treadle style drivetrains (which all full torque throughout their movement) would reign supreme. And yet they don't - in fact, they generally prove inferior to circular motion drivetrains.



Go back to the drawing board and try again.

[Spoker]

Between a square ring- and a round one, there will be an optimal shape.
Explain why a round one is that?

[martl]

Originally Posted by dnc

Soleus muscle

" Function

The action of the calf muscles, including the soleus, is plantarflexion of the foot (that is, they increase the angle between the foot and the leg). They are powerful muscles and are vital in walking, running, and keeping balance. The soleus specifically plays an important role in maintaining standing posture; if not for its constant pull, the body would fall forward.

Also, in upright posture, the soleus is responsible for pumping venous blood back into the heart from the periphery, and is often called the skeletal-muscle pump, peripheral heart or the sural (tricipital) pump.

Soleus muscles have a higher proportion of slow muscle fibers than many other muscles. In some animals, such as the guinea pig and cat, soleus consists of 100% slow muscle fibers. Human soleus fiber composition is quite variable, containing between 60 and 100% slow fibers.

The soleus is the most effective muscle for plantarflexion in a bent knee position. This is because the gastrocnemius originates on the femur, so bending the leg limits its effective tension. During regular movement (i.e., walking) the soleus is the primary muscle utilized for plantarflexion due to the slowtwitch fibers resisting fatigue. "

Thanks!

So, you're talking about pedalling with a pronounced usage of the ankle joint, as opposed to "fixing" the ankle and pedalling mostly from the upper thigh (aka round pedal stroke)?
*not one* of the gizmos offered does anything for a better "round pedal stroke".


Also i seriously doubt the theory that the soleus is left idle in natural pedalling. There are many muscles involved in a natural pedalstroke. This can be visualized when mainpulating some of the fixed points the human body utilizes when pedalling; Imagine using a very slippery saddle, or riding freefand without holding on to the handlebars, it will change very significantly the way you ride, and you can't do it the same way as you would normally - this shows that even muscles as far away as in the back and in the shoulders and arms are involved.
Especially the "slippery saddle" (thought) experiment proves that we do indeed not "trample down" only. (and even those who do mostly trampling are not necessarily slow, a study once uncovered one who was an olympic gold medallist in the team track pursuit..)

If there *is* a misconception of the dynamics of the pedalstroke, i think it is made by the people propagating devices designed to "improve" the pedalstroke like oval rings or other more complicated devices like the cyfly i mentioned. They assume JoeAverage uses just two muscles to pedal and that all force is applied only in a completely vertical direction.

It isn't like that.

One does not simply have additional muscles idling around which would improve performance if one found a way to use them. (There are bikes with a second crank *for the arms* and even those aren't a bit faster.)

Its a complicated system of force stress/recovery and holding/moving power, how much wattage the body can put out. What is gained in one point is paid for somewhere else.

What *can* be optimized is, as you said, shifting certain kind of load to muscle groups well fit for it. This won't improve performance in the short term, but may give a minor advantage countering fatigue. I doubt it is significant as there are many, many factors in there, and the body isn't a set of constants, it will adapt.

The more torque (force applied at a right angle to the crank) a rider can apply to his cranks with the mashing technique, the faster he will go in a sprint, but that's not the most effective way to produce sustainable torque for time trials, for that you need the most fatigue resistant muscle like the soleus.
The objective of all these non round shaped chainrings is to try and compensate for the inability of riders to apply effective torque around TDC by prolonging time spent in the 2-4 o'c sector where most effective torque can be applied, but you don't have sufficient time to make the necessary adjustments to your pedalling that will give you this advantage (if any).

Yep, torque is for accelerating. As torque adjustment can also simply be done by using the shifting, systems with variable torque capability like oval chainrings have very little to offer in a very limited range of situations. They *feel* maybe better when starting from 0 speed, like towing a trailer up the ramp of the underground garage, which may account for the immediate "this feels better" effect.

That being said, it may be that riding oval chainrings feel better for you, because their characteristics fit better to your individual way of riding. Nothing wrong with using them, of course. Given the implications (cost, shifting behavior, availability) they aren't worth it for people looking for an edge. Vroome won because his power at anaerobic threshold and his ability to hold it and endure the pain was greater than that of everyone elses.

[dnc]

Originally Posted by martl

Thanks!

So, you're talking about pedalling with a pronounced usage of the ankle joint, as opposed to "fixing" the ankle and pedalling mostly from the upper thigh (aka round pedal stroke)?
*not one* of the gizmos offered does anything for a better "round pedal stroke".


Also i seriously doubt the theory that the soleus is left idle in natural pedalling. There are many muscles involved in a natural pedalstroke. This can be visualized when mainpulating some of the fixed points the human body utilizes when pedalling; Imagine using a very slippery saddle, or riding freefand without holding on to the handlebars, it will change very significantly the way you ride, and you can't do it the same way as you would normally - this shows that even muscles as far away as in the back and in the shoulders and arms are involved.

I am talking about pedalling that can make maximal use of the soleus and ankle, (semi circular) in which each leg concentrates on only 180 deg. of the pedalling circle 11-5 o'c, and eliminates the need for oval rings and all other expensive gizmos. While the ankle appears to be in a fixed position, the angle between foot and lower leg is changing as pedal moves around the circle.

Information from latest research and conclusion,

"We maximized the power that every muscle produced throughout the pedal cycle and came up with patterns that look almost identical to what cyclists do. The differences we saw at the ankle occur during the middle of the recovery portion of the cycle where an active ankle extension would be counter productive. That is, even though soleus could produce more power during that portion of the cycle, doing so would produce negative power on the crank."
" Thus, during maximal cycling, humans maximize muscle power at the hip and knee, but the ankle acts to transfer (instead of maximize) power. "

[Mark McM]

Originally Posted by Spoker

Between a square ring- and a round one, there will be an optimal shape.
Explain why a round one is that?

The problem here is that chainring shape does not change the angles or leverage of the joints and muscles. Regardless of the shape of the chainrings, the pedals still go around in a perfect circle. In addition, the 3 joints between the pelvis and pedals (hip, knee and ankle), provide an extra degree of freedom to leg extension, which allows the rider to naturally adapt their leg force/speed through the pedal stroke to maximize power/energy delivery (as has been seen in studies of pedal stroke with elliptical chainrings).

[martl]

Originally Posted by dnc

I am talking about pedalling that can make maximal use of the soleus and ankle, (semi circular) in which each leg concentrates on only 180 deg. of the pedalling circle 11-5 o'c, and eliminates the need for oval rings and all other expensive gizmos. While the ankle appears to be in a fixed position, the angle between foot and lower leg is changing as pedal moves around the circle.

Information from latest research and conclusion,

"We maximized the power that every muscle produced throughout the pedal cycle and came up with patterns that look almost identical to what cyclists do. The differences we saw at the ankle occur during the middle of the recovery portion of the cycle where an active ankle extension would be counter productive. That is, even though soleus could produce more power during that portion of the cycle, doing so would produce negative power on the crank."
" Thus, during maximal cycling, humans maximize muscle power at the hip and knee, but the ankle acts to transfer (instead of maximize) power. "

This conclusion does not say whether that is a good or bad thing, it merely states an observation. The example of the bike with a second crank for arm use shows that nothing is to be gained by involving more muscles, so the limiting factor has to be searched somewhere else.

Which supports my point that devices designed to involve different muscle groups, or claim to improve "power transfer", can not succeed, and also, it is insignificant whether one practices techinque to perform a perfect "round" pedalstroke or not.

[Mark McM]

Originally Posted by martl

Which supports my point that devices designed to involve different muscle groups, or claim to improve "power transfer", can not succeed, and also, it is insignificant whether one practices techinque to perform a perfect "round" pedalstroke or not.

Before going any further, I think we need to define the goals of potential different muscle usage. Is it maximum short term power (i.e. a sprint)? Is it maximum sustained power (like a TT)? The number and usage of the muscles may be very different for each.

[dnc]

Originally Posted by Mark McM

Before going any further, I think we need to define the goals of potential different muscle usage. Is it maximum short term power (i.e. a sprint)? Is it maximum sustained power (like a TT)? The number and usage of the muscles may be very different for each.

The soleus technique I am referring to (semi circular) is for use in flat TT's or anywhere uninterrupted high gear maximal torque can be applied. Because of its lower gear effect, mashing is best for sprinting. It's only a matter of switching technique depending on the type of power you need. There is a simple explanation as to why adding hand cranks will not improve power output, two independent actions that split the brain's concentration. A similar type of problem (split concentration) arises when you try to extend your power application beyond 180 deg. as in the circular style. It does not happen in rowing where arm and leg power are used. Arm power can be used for resistance to increase soleus power at the simultaneous switchover of max force application from one leg to the other, because like rowing it is one combined action and both lines are close to parallel. With the correct aerobar equipment this soleus technique can eliminate the two root causes of the worst lower back pain that only occurs when riding a bike.

[martl]

Originally Posted by dnc

There is a simple explanation as to why adding hand cranks will not improve power output, two independent actions that split the brain's concentration. A similar type of problem (split concentration) arises when you try to extend your power application beyond 180 deg. as in the circular style. It does not happen in rowing where arm and leg power are used. Arm power can be used for resistance to increase soleus power at the simultaneous switchover of max force application from one leg to the other, because like rowing it is one combined action and both lines are close to parallel. With the correct aerobar equipment this soleus technique can eliminate the two root causes of the worst lower back pain that only occurs when riding a bike.

Performing two independent actions simultaneously works very well, as any swimmer, or, for that matter, musician/guitarist/drummer etc. will tell you, all actions where technique is quite important. Turning one or two cranks is trivial in comparison.

The reason why the hand-crank bicycle doesn't work is because you just don't get more power-over-time output by involving more muscles (you *do* get better max power under circumstances, at a cost - faster fatigue).

The limiting factor is: body takes oxygen in, and a certain amount of that, the bit that is not used pumping blood, operating the brain, generating heat, digesting food etc, in general: keeping you alive, can be sent to the muscles for generating motion.
That % is a bit of a constant with vary limited variation. Involving more muscles, or the same muscles for a longer time in the same time period, does less and less the longer the timespan is; Rowers may see an effect in their 6-8min races, cyclists don't.
Normal cycling is an activity at a load level that can be maintained as long as the secondary ingredient for burning the oxygen one breathes in is available.

That is the *primary* effect (of which, for cyclists, there is none to speak of). You are talking a lot about what i would call *secondary effects* - slowly growing pain in certain body areas, fatigue. These effects may be influenced by changing the way one uses certain muscles, and in what way and to what extent.

[Louis]

Imagine how much faster you'd be if you put the oval chainrings on these cranks: