SPD's power advantage....Myth?
Comments
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rjsterry wrote:The Beginner wrote:Even standing up the most force you can apply to the pedals is your body weight
Not sure I agree with this. Your leg miscles are more than capable of lifting your body weight and quite a lot more.
Newton, every action has an equal and opposite reaction, exert more force than your body weight and you raise your body until your leg is straight the only force then acting down is your body weight, so as I stated, the most force you can apply is your body weight. (leaving aside the very short time taken to raise your body, which is minimal since you exert force at the top of the pedal stroke anyway.
SimonCurrently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
I shouldn't offer my thoughts here because I don't really know what I am talking about, but assuming you cannot push down and pull up at the same time that surely does not mean there is no advantage to SPDs beyond the rider being attached to the bike. You can pull up when clipped in and so you have the opportunity to vary how much force is pulling and how much is pushing. Even if the power output is much the same, it gives you the chance to vary what muscles are being used and to what degree at any given time.
Apologies if the above is utter balls0 -
Umm, I think you are getting your bike confused with the stepper machine at the gym. Remember that you have handlebars and a saddle with which to lever your bicycle forwards. By your reasoning, you could only cycle as fast as you weigh.The Beginner wrote:rjsterry wrote:The Beginner wrote:Even standing up the most force you can apply to the pedals is your body weight
Not sure I agree with this. Your leg miscles are more than capable of lifting your body weight and quite a lot more.
Newton, every action has an equal and opposite reaction, exert more force than your body weight and you raise your body until your leg is straight the only force then acting down is your body weight, so as I stated, the most force you can apply is your body weight. (leaving aside the very short time taken to raise your body, which is minimal since you exert force at the top of the pedal stroke anyway.
Simon
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snailracer wrote:Yes, but how many tried out strapless toe cups in between?
Me for about a week after going from flats. I then put the straps on as I realised how useless they were without them. Then I switched to SPD's after some high speed crashes when I had a lot of trouble disentagling myself from the bike afterwards.
Mike0 -
Always Tyred wrote:
Umm, I think you are getting your bike confused with the stepper machine at the gym. Remember that you have handlebars and a saddle with which to lever your bicycle forwards. By your reasoning, you could only cycle as fast as you weigh.The Beginner wrote:rjsterry wrote:The Beginner wrote:Even standing up the most force you can apply to the pedals is your body weight
Not sure I agree with this. Your leg miscles are more than capable of lifting your body weight and quite a lot more.
Newton, every action has an equal and opposite reaction, exert more force than your body weight and you raise your body until your leg is straight the only force then acting down is your body weight, so as I stated, the most force you can apply is your body weight. (leaving aside the very short time taken to raise your body, which is minimal since you exert force at the top of the pedal stroke anyway.
Simon
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No you can pull down on the bars, but as they aren't inline with your feet, that will induce a pitching moment, pitching you forward, they are only a small benefit, as for the saddle, not sure how that stops you going up, allowing you to push down harder?
SimonCurrently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
The Beginner wrote:
No you can pull down on the bars, but as they aren't inline with your feet, that will induce a pitching moment, pitching you forward, they are only a small benefit, as for the saddle, not sure how that stops you going up, allowing you to push down harder?
Simon
If the force to the pedals is limited by one's body weight, you should ring Chris Hoy and tell him to replace his squat routine with a donut-eating routine.
Aside from the point that the force to the pedals isn't limited to body weight because F=MA, it is pretty obvious that one can pull up on the bars in order to push down harder on the pedals, especially when climbing. One uses the bars to stop one's body from rising. It's the same as grabbing on to a car bumper and driving one's heels into the ground. It's the same as a deadlift motion. On a bicycle you can certainly pull up on the bars in the direction opposite the downward force from your feet. Furthermore, if I push with one foot and pull with the other, my body weight isn't limiting anything, since I am applying the force around the axle.0 -
There are backwards and forwards and side to side directions as well as the uppy downy direction, you know?The Beginner wrote:No you can pull down on the bars, but as they aren't inline with your feet, that will induce a pitching moment, pitching you forward, they are only a small benefit, as for the saddle, not sure how that stops you going up, allowing you to push down harder?
Simon
In these circumstances, try working back from the solution. Clearly Cancellara can generate hugely more force on the pedals, to thereby go faster, than me. He probably weighs about the same. I can stand up. Indeed I can even use my leg muscles to jump, overcoming my body weight.
So, rationally, if I can exert more force on the pedals than my body weight and Cancellara is a little bit better than me, there must be something more complicated going on than Newton's first law, in one plane of motion.0 -
The clips that can accommodate straps are not the ones I am talking about.mudcovered wrote:snailracer wrote:Yes, but how many tried out strapless toe cups in between?
Me for about a week after going from flats. I then put the straps on as I realised how useless they were without them. Then I switched to SPD's after some high speed crashes when I had a lot of trouble disentagling myself from the bike afterwards.
Mike
I am referring to these:
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Dr Forrester didn't say you couldn't pull up on the pedals, her point was that it interferes with the downstroke which is what riders should be concentrating on. Perhaps she has not found many riders who could push AND pull effectively at the efficient high rpms advocated (SS & fixie riders excused).Jonny_Trousers wrote:I shouldn't offer my thoughts here because I don't really know what I am talking about, but assuming you cannot push down and pull up at the same time that surely does not mean there is no advantage to SPDs beyond the rider being attached to the bike. You can pull up when clipped in and so you have the opportunity to vary how much force is pulling and how much is pushing. Even if the power output is much the same, it gives you the chance to vary what muscles are being used and to what degree at any given time.
Apologies if the above is utter balls
As for the gravity thing, she may have been talking about the hypothetical situation where a rider ONLY pulls up on the pedals, in which case gravity does work against you.
Looking at her bio, I am inclined to believe what she says, no salt required.0 -
Soft engine mounts, sprung clutch plates and rubber bushings ("donuts" as you call them) were all introduced on passenger cars to reduce vibration and has nothing to do with losses.meanredspider wrote:jimmypippa wrote:
You can run on concrete in bare feet.
For how long and how often? I suggest at my age and size I'd soon suffer from plantar fasciitis if I tried this.
It's slightly off the point, however. Trainer soles are typically designed to absorb impacts. They do so by absorbing energy which is released as heat. Hi-end cycling shoes are the exact opposite. They are as stiff and hard as possible.
It's a principle that is applied in motor racing transmissions - ultra-stiff engine mounts, unsprung clutch plates, aluminium (rather than rubber) transmission donuts. All of these reduce parasitic losses.0 -
Disturbing. Having letters after your name doesn't stop you from talking bollicks. She's basically saying that pulling up distracts you from pressing down and that therefore pulling up distracts you from pushing down.snailracer wrote:Looking at her bio, I am inclined to believe what she says, no salt required.
That's like saying that changing gear distracts you from steering. Its absolute nonsense to take the assumption that as it makes it more difficult (i.e. its a slightly more complicated muscle combination) "its a disadvantage". This only follows if you presume that it can't be learnt.
Lets face it, there are activities which humans are capable of which are far more complicated than riding a bike, so adding the option of pulling up when climbing, or squeezing the last bit out of a pedal stroke at full effort is hardly going to overload the donkey.0 -
meanredspider wrote:jimmypippa wrote:
You can run on concrete in bare feet.
For how long and how often? I suggest at my age and size I'd soon suffer from plantar fasciitis if I tried this.
It's slightly off the point, however. Trainer soles are typically designed to absorb impacts. They do so by absorbing energy which is released as heat. Hi-end cycling shoes are the exact opposite. They are as stiff and hard as possible./quote]
It is off topic, but If I am running on tiptoes, I have the best part of a foot's length in "sprung" height where my calf muscles can absorb the impact. And return a lot of the energy in the spring back.
I'll try to dig up some actual references, which I have seen elsewhere.0 -
Running shoes have a different purpose to cycling shoes. The comparison a moot point.
Running is high impact on your joints and shin bones. Running on hard surfaces in thin hard shoes damages your knees and can cause shin splints (micro fractures in your shin bones) so running shoes are soft so as not to ruin your body. You lose power but you run in comfort.
Cycling is low impact on your joints (unless you crash of course) so there is no need for cushioning. The shoes are made as stiff as possible for efficiency. SPDs are much more efficient than flats because you can use many more muscles to turn the cranks with proper technique. Maybe flats are more useful on technical terrain or for people with no confidence to be clipped in. Only when climbing a steep hill does SPD v flat reach parity, assuming your feet wont slip on your flats and your shoes are decent. Only when you can't climb in the saddle though. Any other time SPDs win on the energy transfer front.God made the Earth. The Dutch made The Netherlands
FCN 11/12 - Ocasional beardy0 -
Just keeping upright taxes this donkeyAlways Tyred wrote:
Disturbing. Having letters after your name doesn't stop you from talking bollicks. She's basically saying that pulling up distracts you from pressing down and that therefore pulling up distracts you from pushing down.snailracer wrote:Looking at her bio, I am inclined to believe what she says, no salt required.
That's like saying that changing gear distracts you from steering. Its absolute nonsense to take the assumption that as it makes it more difficult (i.e. its a slightly more complicated muscle combination) "its a disadvantage". This only follows if you presume that it can't be learnt.
Lets face it, there are activities which humans are capable of which are far more complicated than riding a bike, so adding the option of pulling up when climbing, or squeezing the last bit out of a pedal stroke at full effort is hardly going to overload the donkey.
I take your point, I've seen bicycle acrobats doing one-armed handstands on the bars whilst rolling backwards.0 -
Biographical Information for Dr Auriel Forrester:
Current Cycling Honours
UCI World Champion : Masters Pursuit - Women 40-44 (1998, 1999, 2000 and 2001)
UCI World Silver Medalist : Masters 500m TT - Women 40-44 (2000, 2001)
World Record Holder : Masters Pursuit - Women 40-44 (1999,2000 2001 and 2002)
World Veterans Hour Record Holder - Women 40 plus (1998-)
BCF Womens Omnium Championships - Silver (1999)
Previous Sporting Honours
County Cross Country Running Champion - women veterans (1993/4)
County 10K Road Running Champion - women seniors and veterans (1994)
BBAR Championship Team (Wyevern CC) (1986)
National Championship Team - 25 and 50 miles (1986)
RTTC medalist : 25, 50 and 100 miles (1982/3)
Great Britain Women's Road squad (1982-4)
Icknield Road Club Ladies BAR (1995-99)
North Middx and Herts Ladies Champion (1996,1998)
Qualifications
PhD Human Physiology (1983)
BASES Accredited Sport Scientist
BCF and ABCC Senior Coach and Coach Education Tutor
RSA and APT qualified fitness instructor and personal trainer
Sports Coach UK Senior Tutor
World Class Performance Advisor
Quality Assurance Agency assessor for Higher Education
Sport England committee member for Bedfordshire Sport and Eastern Region
Member of Eastern Region Sport Science and Sports Medicine development programme
External examiner and advisor for various bodies in relation to higher education, coaching and performance analysis including University of Salford, Napier University and Barnfield College, Luton.0 -
Did she say that? Can we have a link or something? After i quick qoogle-search, i didn't find nothing.0
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nastybishop wrote:Did she say that? Can we have a link or something? After i quick qoogle-search, i didn't find nothing.
2nd hit on a google search! http://www.scientific-coaching.com/Scientific%20Coaching/Biography[/url]0 -
The Beginner wrote:rjsterry wrote:The Beginner wrote:Even standing up the most force you can apply to the pedals is your body weight
Not sure I agree with this. Your leg miscles are more than capable of lifting your body weight and quite a lot more.
Newton, every action has an equal and opposite reaction, exert more force than your body weight and you raise your body until your leg is straight the only force then acting down is your body weight, so as I stated, the most force you can apply is your body weight. (leaving aside the very short time taken to raise your body, which is minimal since you exert force at the top of the pedal stroke anyway.
Simon
You can pull up hard against the high gear ie at very low revs. The down stroke foot simply does not drop fast enough . At high revs the effect dissapears, as you can not pull up as fast as you can push down. You cannot do this when standing on the pedals only of course, but with the bars and leverage, you can.0 -
Oh, she must be right then, not withstanding the fact that she disagrees with the rest of the elite cycling world.snailracer wrote:Biographical Information for Dr Auriel Forrester:
Current Cycling Honours
UCI World Champion : Masters Pursuit - Women 40-44 (1998, 1999, 2000 and 2001)
UCI World Silver Medalist : Masters 500m TT - Women 40-44 (2000, 2001)
World Record Holder : Masters Pursuit - Women 40-44 (1999,2000 2001 and 2002)
World Veterans Hour Record Holder - Women 40 plus (1998-)
BCF Womens Omnium Championships - Silver (1999)
Previous Sporting Honours
County Cross Country Running Champion - women veterans (1993/4)
County 10K Road Running Champion - women seniors and veterans (1994)
BBAR Championship Team (Wyevern CC) (1986)
National Championship Team - 25 and 50 miles (1986)
RTTC medalist : 25, 50 and 100 miles (1982/3)
Great Britain Women's Road squad (1982-4)
Icknield Road Club Ladies BAR (1995-99)
North Middx and Herts Ladies Champion (1996,1998)
Qualifications
PhD Human Physiology (1983)
BASES Accredited Sport Scientist
BCF and ABCC Senior Coach and Coach Education Tutor
RSA and APT qualified fitness instructor and personal trainer
Sports Coach UK Senior Tutor
World Class Performance Advisor
Quality Assurance Agency assessor for Higher Education
Sport England committee member for Bedfordshire Sport and Eastern Region
Member of Eastern Region Sport Science and Sports Medicine development programme
External examiner and advisor for various bodies in relation to higher education, coaching and performance analysis including University of Salford, Napier University and Barnfield College, Luton.
Has she taken any measurements, or is her opinion based on... um.. her opinion and backed up by her... um... CV.
Read that lot critically, and you'll see two qualifications and then some things done with those qualifications. (Not counting fitness instruction qualifications - fitness instructors do things like tell you to use a power plate - so its not a qualification, its a badge)
Here's a question - does she ride with flats, or clipless pedals?0 -
With SPDs you can pedal UP and DOWN - with flats you can only push down. What is there no to understand?0
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This is an interesting read, from about page 119:
http://books.google.co.uk/books?id=msdT ... st&f=false0 -
gbsahne wrote:nastybishop wrote:Did she say that? Can we have a link or something? After i quick qoogle-search, i didn't find nothing.
2nd hit on a google search! http://www.scientific-coaching.com/Scientific%20Coaching/Biography[/url]
This is just a personal note...Where does she claim the superiority of flat pedals? I mean...i do not want to cast doubts ..but her claim is so surprising that i want to read it myself.0 -
I am not aware of any elite cyclist who has said whether they do, or do not, pull up on the pedals. Just because clipless pedals can be used for pulling, doesn't mean the elite guys actually do that. If Dr F's comments are taken at face value, then they probably don't. And she has probably had more contact with the elite than we have.Always Tyred wrote:
Oh, she must be right then, not withstanding the fact that she disagrees with the rest of the elite cycling world.snailracer wrote:Biographical Information for Dr Auriel Forrester:
Current Cycling Honours
UCI World Champion : Masters Pursuit - Women 40-44 (1998, 1999, 2000 and 2001)
UCI World Silver Medalist : Masters 500m TT - Women 40-44 (2000, 2001)
World Record Holder : Masters Pursuit - Women 40-44 (1999,2000 2001 and 2002)
World Veterans Hour Record Holder - Women 40 plus (1998-)
BCF Womens Omnium Championships - Silver (1999)
Previous Sporting Honours
County Cross Country Running Champion - women veterans (1993/4)
County 10K Road Running Champion - women seniors and veterans (1994)
BBAR Championship Team (Wyevern CC) (1986)
National Championship Team - 25 and 50 miles (1986)
RTTC medalist : 25, 50 and 100 miles (1982/3)
Great Britain Women's Road squad (1982-4)
Icknield Road Club Ladies BAR (1995-99)
North Middx and Herts Ladies Champion (1996,1998)
Qualifications
PhD Human Physiology (1983)
BASES Accredited Sport Scientist
BCF and ABCC Senior Coach and Coach Education Tutor
RSA and APT qualified fitness instructor and personal trainer
Sports Coach UK Senior Tutor
World Class Performance Advisor
Quality Assurance Agency assessor for Higher Education
Sport England committee member for Bedfordshire Sport and Eastern Region
Member of Eastern Region Sport Science and Sports Medicine development programme
External examiner and advisor for various bodies in relation to higher education, coaching and performance analysis including University of Salford, Napier University and Barnfield College, Luton.
Has she taken any measurements, or is her opinion based on... um.. her opinion and backed up by her... um... CV.
Read that lot critically, and you'll see two qualifications and then some things done with those qualifications. (Not counting fitness instruction qualifications - fitness instructors do things like tell you to use a power plate - so its not a qualification, its a badge)
Here's a question - does she ride with flats, or clipless pedals?
A power plate will quickly tell you whether or not you are contributing on the upstroke - presumably she has used these in her work.
I am not trashing clipless pedals, their popularity speaks for itself, I am simply questioning some of the claims people make about them.0 -
nastybishop wrote:gbsahne wrote:nastybishop wrote:Did she say that? Can we have a link or something? After i quick qoogle-search, i didn't find nothing.
2nd hit on a google search! http://www.scientific-coaching.com/Scientific%20Coaching/Biography[/url]
This is just a personal note...Where does she claim the superiority of flat pedals? I mean...i do not want to cast doubts ..but her claim is so surprising that i want to read it myself.
http://www.bikeradar.com/fitness/articl ... ttle-27049
She doesn't, but she does pour cold water on the claim that pulling up helps you climb hills.0 -
Is she seriously claiming this when you are honking out of the saddle up a hill? I damn near rip the heels of my shoes off when I am doing that.snailracer wrote:nastybishop wrote:gbsahne wrote:nastybishop wrote:Did she say that? Can we have a link or something? After i quick qoogle-search, i didn't find nothing.
2nd hit on a google search! http://www.scientific-coaching.com/Scientific%20Coaching/Biography[/url]
This is just a personal note...Where does she claim the superiority of flat pedals? I mean...i do not want to cast doubts ..but her claim is so surprising that i want to read it myself.
http://www.bikeradar.com/fitness/articl ... ttle-27049
She doesn't, but she does pour cold water on the claim that pulling up helps you climb hills.
Ineresting book link, btw. Sort of contradicts her, doesn't it, by suggesting that making the upstroke less detrimental, it does contribute.0 -
Always Tyred wrote:
Is she seriously claiming this when you are honking out of the saddle up a hill? I damn near rip the heels of my shoes off when I am doing that.snailracer wrote:nastybishop wrote:gbsahne wrote:nastybishop wrote:Did she say that? Can we have a link or something? After i quick qoogle-search, i didn't find nothing.
2nd hit on a google search! http://www.scientific-coaching.com/Scientific%20Coaching/Biography[/url]
This is just a personal note...Where does she claim the superiority of flat pedals? I mean...i do not want to cast doubts ..but her claim is so surprising that i want to read it myself.
http://www.bikeradar.com/fitness/articl ... ttle-27049
She doesn't, but she does pour cold water on the claim that pulling up helps you climb hills.
Ineresting book link, btw. Sort of contradicts her, doesn't it, by suggesting that making the upstroke less detrimental, it does contribute.
"Less detrimental" is hardly contributing, it means the upstroke gets in the way less, no?
Page 133:
"Compared to recreational cyclists, elite cyclists generally have reduced negative force effectiveness during the upstroke..."
IOW, an elite rider's foot still pushes down on the upstroke, just less than us mortals.
Page 133:
"Effective forces during the upstroke are less negative and less counterproductive at higher work rates (cycling power) for a given cadence, and may even be positive during sprinting and climbing."
That was the nearest the author came to saying pulling up helps, the word "may" suggests it was never actually observed.
Page 138:
"...forces during standing climbing within the upstroke were still counterproductive (opposed crank rotation) and larger in magnitude than those seen in seated climbing."
IOW, still no actual pulling up on the pedal, when climbing either standing or seated.
Page 132:
"Cyclists may move their feet in circles during pedaling, but applied force and developed torque appear in no way circular".
IOW, effective pedaling in circles was not observed in a survey of 125 competitive cyclists.
I suspect that a rider consciously pulls up on the upstroke, but the leg simply can't keep up with the rising pedal at the cadences tested.0 -
What does it matter if its less detrimental or positive?
What counts is what you are comparing it to.0 -
Yes, I believe cadence is a huge factor here on how much upstroke force can be effectively generated. Most studies I have seen show that for elite cyclists at optimum cadence, the effect is negligible, and actively trying to produce an upstroke is less efficient.0
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cycling. In addition, instructing the rider to
employ a certain pedaling technique did not result in
significant changes in mechanical effectiveness and gross
efficiency when compared with the preferred pedaling style,
unless the rider was instructed to pull up actively on the
pedal. These findings suggest that during cycling, the
extensor muscles are more efficient power producers than
the flexor muscles. Our
I really don't have the energy to put this statement from that paper into context, so apologies if I'm misinterpreting, but doesn't this say that its better to pull up? And that big muscles produce more power than small muscles?
Another problem I had with the study, on a quick scan, was that the authors are making instantaneous comparisons. Take a rider with a preferred style and musculature to suit and them ask them to change it and see if they are any better. How is that a fair comparison? The only sport I got much of an understanding of this sort of thing with was rowing. In that sport, the rower can optimise their body for a truly dreadful technique that can give them long term physical problems. Ask them to change something dramatic, such as hip angle at the finish (i.e not slumping back on the hips at the end of the stroke) and they'll go immediately slower. Lower abs and mid back will be wrecked in half the normal time. Does this make it incorrect? No. Come back a year later and they are better than they were to begin with.
I'm sure the same concept applies to cycling.
My reading of the previous book result was that by trying to pull up, youmade the negative force during the upstroke less negative than it would have been had you not tried to pull up, the net torque thereby increasing. The effect lessens at higher cadence (where for a given power, less force is applied) and increases at higher power output and during climbing (a tortology I think). Is that correct? I didn't see anything to suggest that trying pull up made things worse.
Btw - going back a bit, a power plate is a pointless vibrating disc they have at gyms at the moment. Gym instructors duly show newbies how it works, despite the fact that the medical studies on the company's own website clearly state that there is no measureable effect of the device, with the possible exception of the elderly, where the results were inclonclusive. But hey, most customers won't get as far as reading any of the studies critically.0
