Improving pedalling efficiency

Trev The Rev

bernithebiker wrote:

Trev The Rev wrote:

Elite cyclists simply push down harder, more frequently, than the rest of us. Focus on that.

This is simply stating the obvious. If I could apply more force at a higher cadence I would, wouldn't I?

Trev The Rev wrote:

People confuse "smooth" pedalling with "circular" or "trying to apply force all the way round the stroke" pedalling. They are not the same thing.

Good cyclists can be seen to have a 'smooth' pedal motion. They are not necessarily applying an upward force, but their technique is good, and they are not stomping like many beginners do.

Trev The Rev wrote:

Powerful riding is all about the downstroke. Smooth pedalling is about a powerful downstroke with good muscular coordination turning on/off at the right times and done frequently (as well as having a well fitted bicycle to start with).

Again, stating the obvious. Clearly the vast majority of your power comes at the downstroke. But even better is a powerful downstroke and a smooth technique.

On long rides, when I need to be efficient, and my cadence is a bit lower than usual, I will continue to pedal circles, happy in the knowledge that it's saving me energy, and regretfully, I will be ignoring your advice.

It isn't my advice you will be ignoring.

cyco2

I am definately a pusher which I learned to do so I could go faster, many years ago. I concentrated on the down stroke and left the up stroke to sort itself out. The upstroke is used for accelerating up climbs and start of sprints.
Now I like to look at elite riders and see what they do. I have watched riders such as Christian House, the Brownlees, and the Olympic track riders and they all lift their heels when on full bore. This allows them to spin faster and push longer on the down stroke.

RChung

bernithebiker wrote:

Trev The Rev wrote:

People confuse "smooth" pedalling with "circular" or "trying to apply force all the way round the stroke" pedalling. They are not the same thing.

Good cyclists can be seen to have a 'smooth' pedal motion. They are not necessarily applying an upward force, but their technique is good, and they are not stomping like many beginners do.

Which of these two groups is "stomping," and which is "pulling up"?

On long rides, when I need to be efficient, and my cadence is a bit lower than usual, I will continue to pedal circles, happy in the knowledge that it's saving me energy, and regretfully, I will be ignoring your advice.

How much energy are you saving, and how are you measuring it?

bernithebiker

RChung wrote:

Which of these two groups is "stomping," and which is "pulling up"?

Neither Group is an extreme example IMO, but Group 2 has a smoother technique than 1, and the positive contribution over 1/2 the stroke (as opposed to negative) reduces the effect of the lower torque downstroke. Different riders will react differently. Some may struggle to do anything positive on the upstroke, some may find it easy, just as some riders climb in the saddle and some out. I am in the latter group in both cases.

RChung wrote:

How much energy are you saving, and how are you measuring it?

I have no power meter, but I know that if I bog down slightly, consciously pedaling circles will pick me back up and maintain the pace. I can only conclude therefore, that it slightly resting my prime muscles. (N.B. I cannot maintain this style indefinitely).

bernithebiker

One more thing;

Many times I have seen pros pull out of their pedals, sometimes sprinting, sometimes climbing.

And pedal spring tension on road pedals is quite high - Look Keo Blades can be had in 12 or 16Nm.

Why?

Could it possibly be that there is a danger of pulling out of the pedal on the upstroke? And if so, then that is quite some force being developed, to pull past a 16Nm spring.....

Tom Dean

It is normal to pull on the upstroke when sprinting or in hard accelerations out of the saddle. These are not situations when pedalling 'efficiency' is an important factor.

dzp1

Its on the page marked 101..

(8MB download)

http://www.edb.utexas.edu/coyle/pdf%20library/(40)%20Coyle,%20Feltner%20et%20al,%20Physiological%20and%20biochemical%20determinants%20of%20elite%20endurance%20cycling%20performance,%20Med%20and%20Sci%20in%20Sports%20and%20Exercise,%2023,%2093-107,%201991.pdf

(BR forum software messed up the link)

Thats my evening sorted

RChung

bernithebiker wrote:

RChung wrote:

Which of these two groups is "stomping," and which is "pulling up"?

Neither Group is an extreme example IMO, but Group 2 has a smoother technique than 1, and the positive contribution over 1/2 the stroke (as opposed to negative) reduces the effect of the lower torque downstroke.

Well, most people *would* say that Group 2 has smoother technique than Group 1. Group 1 stomped harder and pulled up less than Group 2. However, Group 1 were elite national level cyclists while Group 2 were very good elite "state-level" cyclists. Group 1 produced higher average power, better TT times, and had marginally higher cycling economy (measured as watts/L/min).

bernithebiker wrote:

RChung wrote:

bernithebiker wrote:

On long rides, when I need to be efficient, and my cadence is a bit lower than usual, I will continue to pedal circles, happy in the knowledge that it's saving me energy, and regretfully, I will be ignoring your advice.

How much energy are you saving, and how are you measuring it?

I have no power meter

If you have no power meter and you haven't been in a lab to measure your O2 consumption you can't know how efficient (or inefficient) you are. So when you said "[you're] happy in the knowledge that it's saving [you] energy" you're actually saying you're happy in your ignorance.

bernithebiker

RChung wrote:

Well, most people *would* say that Group 2 has smoother technique than Group 1. Group 1 stomped harder and pulled up less than Group 2. However, Group 1 were elite national level cyclists while Group 2 were very good elite "state-level" cyclists. Group 1 produced higher average power, better TT times, and had marginally higher cycling economy (measured as watts/L/min).

Well if Group 1 were significantly higher level cyclists, you would expect them to do faster TT's and produce more power wouldn't you?

RChung wrote:

If you have no power meter and you haven't been in a lab to measure your O2 consumption you can't know how efficient (or inefficient) you are. So when you said "[you're] happy in the knowledge that it's saving [you] energy" you're actually saying you're happy in your ignorance.

Hey, it works for me, and I'm happy to have as many weapons in my armoury as I can. When I climb a big col, I climb best (fastest) 50% in, 50% out of the saddle. Can I show you O2 and power figures? No. But I can use a stopwatch.

bernithebiker

Tom Dean wrote:

It is normal to pull on the upstroke when sprinting or in hard accelerations out of the saddle. These are not situations when pedalling 'efficiency' is an important factor.

But Trev says he goes just as fast with flat pedals. Can we assume he doesn't sprint or accelerate then?!

Tom Dean

He mentioned these specific sorts of situations.

danowat

RChung wrote:

Group 1 produced higher average power, better TT times, and had marginally higher cycling economy (measured as watts/L/min).

So in laymans terms, those that pull up less produce better results?

ncr

Trev The Rev wrote:

I hope the following is clear.

Powerful riding is all about the downstroke. Smooth pedalling is about a powerful downstroke with good muscular coordination turning on/off at the right times and done frequently (as well as having a well fitted bicycle to start with).

It's about the well coordinated firing on/off of the respective leg's down stroke.

What are the right times for turning on/off.

dzp1

bernithebiker wrote:

Well if Group 1 were significantly higher level cyclists, you would expect them to do faster TT's and produce more power wouldn't you?

The work suggests that the PROPORTION of the riders effort devoted to the downward action is higher in elite cyclists. Its not just saying they produce more power.

It also shows that their upward force is less - roughly just unweighting instead of pulling up as per the slower group

I'd like to know if this research has been confirmed or repeated in later papers.

RChung

danowat wrote:

RChung wrote:

Group 1 produced higher average power, better TT times, and had marginally higher cycling economy (measured as watts/L/min).

So in laymans terms, those that pull up less produce better results?

No, that's a bridge too far. In layman's terms, those that produce better results pull up less (and stomp down harder). That doesn't mean that if we pull up less and stomp down harder that we'll improve our performances; it does mean that pedaling technique (in the classic "smooth round circle" sense) doesn't seem to be very important.

[Edited to add:] BTW, as I said above, Group 1 had marginally higher cycling economy than Group 2. The differences weren't statistically significant (but statistical significance is more a statement about sample size than it is about the difference itself). Here are the cycling economies for the riders in the study:



What this means is that, although not statistically significant, there's a hint that stomping down harder and pulling up less didn't seem to cost more in terms of economy of energy use. Once again, it's supportive (though not by itself dispositive) that pedaling technique isn't all that important.

marz

Alex_Simmons/RST wrote:

You see, this is where people forget about a little basic physics - when pedalling there is a considerable mass rotating about the crank with some rotational inertia already, plus the leg when at top of the stroke has some gravitational potential energy it transfers to the other leg as it drops down towards the bottom of the stroke and the other leg comes back up (hence why when doing single leg drills, it bear little resemblance to actual pedalling if it's not counterweighted).

Suggest starting by reading through a summary of data on pedalling studies by Jim Martin (a primary expert in this field), then perhaps drill down from there into each of the referenced papers:
http://www.plan2peak.com/files/32_artic ... hnique.pdf

Read it and it says nothing new. Reporting that the most efficient method for producing max power is due to pushing down through the pedals will be a real eye opener for sprinters and track riders. They may have to retrain and develop some pretty strong quads to effectively produce their max power. Oh wait....

What the paper doesn't counter is the effectiveness of a smooth and efficient pedaling stroke (yes, not maintaining an even or equal torque through the entire 360 degrees). While gravity and momentum do drive the pedals through the dead zones, if we only relied on these forces to return our feet to the optimum place to push down again we would have a very jerky movement. Hence why many riders begin to bounce as they increase cadence and leg speed. Their feet are literally being forced off the pedals. Riders have to develop sufficient leg speed to counter centrifugal forces and one leg exercises (of which I not a big fan of) can help some riders induce some muscle memory into the legs.

If the only force/torque that counts is down through the pedals from 11 to 7 o'clock position would a piston type crank be more effective?

danowat

RChung wrote:

danowat wrote:

RChung wrote:

Group 1 produced higher average power, better TT times, and had marginally higher cycling economy (measured as watts/L/min).

So in laymans terms, those that pull up less produce better results?

No, that's a bridge too far. In layman's terms, those that produce better results pull up less (and stomp down harder). That doesn't mean that if we pull up less and stomp down harder that we'll improve our performances; it does mean that pedaling technique (in the classic "smooth round circle" sense) doesn't seem to be very important.

[Edited to add:] BTW, as I said above, Group 1 had marginally higher cycling economy than Group 2. The differences weren't statistically significant (but statistical significance is more a statement about sample size than it is about the difference itself). Here are the cycling economies for the riders in the study:



What this means is that, although not statistically significant, there's a hint that stomping down harder and pulling up less didn't seem to cost more in terms of economy of energy use. Once again, it's supportive (though not by itself dispositive) that pedaling technique isn't all that important.

Ever thought of being a politician?

So pulling up isn't a recommended action??, people consciously pulling up are compromising their riding and are better of letting the pedal action be natural and fluid?

ric/rstsport

when can we introduce power cranks into this thread? surely, a mechanism designed to force you to actively pull up would increase your efficiency, and sustainable power output. Right? Where's Frank Day? ;-)

I miss slowtwitch and Frank.

Robert, can you imagine how good it'd be if we had Frank, Trev and Noel all in one chat?

Ric

RChung

danowat wrote:

So pulling up isn't a recommended action??, people consciously pulling up are compromising their riding and are better of letting the pedal action be natural and fluid?

The 2007 Korff et al. study of experienced cyclists shows that their preferred pedal technique was already pretty good, and exogenously changing their pedal technique to pull up actually decreased their gross metabolic efficiency. This was for endurance cycling, not sprinting; but in sprints we don't really care much about metabolic efficiency anyway.

ric wrote:

Robert, can you imagine how good it'd be if we had Frank, Trev and Noel all in one chat?

http://www.imdb.com/title/tt0800320/

danowat

RChung wrote:

The 2007 Korff et al. study of experienced cyclists shows that their preferred pedal technique was already pretty good, and exogenously changing their pedal technique to pull up actually decreased their gross metabolic efficiency. This was for endurance cycling, not sprinting; but in sprints we don't really care much about metabolic efficiency anyway

Still a bit muddy, but I think the waters have cleared some what.......

ric/rstsport

;-)

Alex_Simmons/RST

Herbsman wrote:

Clipless pedals exist for foot security, not pedaling efficiency.

Correct. Foot security is very important in racing. Most elite BMX riders are using clip in pedals. Downhillers vary between clip in and flat bed.

However there are additional benefits:
- quality of the shoe-pedal interface with quality soles that prevent foot deformation under load, which will vary depending on where the pedal is relative to the foot
- for sprinting / very short duration efforts where pulling up does occur, particularly in standing starts (e.g. track/BMX)
- and to add to the above point by Herbsman, it keeps our feet and legs properly aligned for each pedal stroke, however there are many people who are possibly doing themselves damage with ill fitted cleat placement
- providing us with funniest home video moments as people fail to unclip when stopping and fall on their mates

Ability to generate sustainable aerobic power is barely, if at all compromised by using flat bed pedals, and at least anecdotally, my experience is that people are capable of achieving the same MAP test result with flat bed pedals as with their regular clip pedals.

"Pulling up" or "more circular" pedalling has very little to do with cycling efficiency, indeed most studies on pedal forces demonstrate a reduction in efficiency from such attempts at pedal force application.

I repeat, if you haven't taken the time to look through the Jim Martin paper I listed earlier and the various links/papers he references, then go through those first. It deals with most of the myths.

billreay

Alex,
You are probaly aware that British Cycling make extensive use of the Wattbike (www.wattbike.com). The training guide for the Wattbike has a 12 page section devoted to pedalling technique and how to improve it using the machine's Polar Graph display. Although they don't give references supporting their advice, they presumably read Jim Martin's paper.

ric/rstsport

are you sure they really use the Wattbike (at least for anything other than as a replacement bike in say inclement weather)...

Herbsman

d87heaven wrote:

http://www.ncbi.nlm.nih.gov/pubmed/17545890

RESULTS:

When the participants were instructed to pull on the pedal during the upstroke, mechanical effectiveness was greater (index of force effectiveness=62.4+/-9.8%) and gross efficiency was lower (gross efficiency=19.0+/-0.7%) compared with the other pedaling conditions (index of force effectiveness=48.2+/-5.1% and gross efficiency=20.2+/-0.6%; means and standard deviations collapsed across preferred, circling, and pushing conditions). Mechanical effectiveness and gross efficiency during the circling and pushing conditions did not differ significantly from the preferred pedaling condition.

I take it nobody bothered to read this, as it doesn't seem to have been discussed since you posted it...

Alex_Simmons/RST

billreay wrote:

Alex,
You are probaly aware that British Cycling make extensive use of the Wattbike (http://www.wattbike.com). The training guide for the Wattbike has a 12 page section devoted to pedalling technique and how to improve it using the machine's Polar Graph display. Although they don't give references supporting their advice, they presumably read Jim Martin's paper.

I'm not aware they make extensive use of the Wattbike.

I am aware of their website section on this feature.

I'm also aware of the conversation I had with the scientist inventor/designer of the Wattbike some years ago and his acknowledgement that the polar pedal info on the website is mostly just marketing spin and really should be amended to reflect actual science. Computrainer's spin scan function as described in their manual they pretty much says the same thing as the WB website, just not quite as pretty. Doesn't make it right though. In this instance the marketing guys won out over the science. Pretty common in the bike industry.

Both fell into the cosy trap (as have many before) of assuming more circular force application = better, more efficient/effective pedalling. It's a nice comforting notion, however it's also a load of twaddle.

bahzob

danowat wrote:

RChung wrote:

The 2007 Korff et al. study of experienced cyclists shows that their preferred pedal technique was already pretty good, and exogenously changing their pedal technique to pull up actually decreased their gross metabolic efficiency. This was for endurance cycling, not sprinting; but in sprints we don't really care much about metabolic efficiency anyway

Still a bit muddy, but I think the waters have cleared some what.......

Sorry to disillusion you. The Korff study is just an example of crap science and the fact it remains the most frequently quoted study in this area just shows how much more there is to learn.

It had many issues but my favourite is that it used what must rank as the most stupid metric of any cycling study.

It's measurements for "endurance cycling" were done by asking the "experienced" riders to do intervals of

200W for 6 minutes

This is an utterly feeble effort and just by itself, notwithstanding the other flaws of the experiment invalidates any conclusions it comes to. The real test of any skill is not how it performs at meaningless efforts but under conditions of stress.

It does show though that the experimenters didn't have a clue about what real cyclists actually do when riding, nor do those who continue to blindly parrot this study as if it was the defining word of God.

bahzob

Alex_Simmons/RST wrote:

billreay wrote:

Alex,
You are probaly aware that British Cycling make extensive use of the Wattbike (http://www.wattbike.com). The training guide for the Wattbike has a 12 page section devoted to pedalling technique and how to improve it using the machine's Polar Graph display. Although they don't give references supporting their advice, they presumably read Jim Martin's paper.

I'm not aware they make extensive use of the Wattbike.

I am aware of their website section on this feature.

I'm also aware of the conversation I had with the scientist inventor/designer of the Wattbike some years ago and his acknowledgement that the polar pedal info on the website is mostly just marketing spin and really should be amended to reflect actual science. Computrainer's spin scan function as described in their manual they pretty much says the same thing as the WB website, just not quite as pretty. Doesn't make it right though. In this instance the marketing guys won out over the science. Pretty common in the bike industry.

Both fell into the cosy trap (as have many before) of assuming more circular force application = better, more efficient/effective pedalling. It's a nice comforting notion, however it's also a load of twaddle.

Your cynical opinion but no more than that. Not one that is shared by others, including Bradley Wiggins who, despite having a pedalling style that would put anyone here to shame worked on further improving it last year helping the results that followed.

Guess you have a cynical opinion of him as well. Fine, but its a shame if this is catching and infects others here.

Tom Dean

I expect Wattbike have some evidence showing the usefulness of their polar graph, but they don't want anyone to see it :roll:

bahzob

For those saying "read Jim Martin." I can only assume they havn't followed their own advice.

The vast majority of the studies posted are about crank length. While related to this topic its not directly relevant and is anyway contrary to the actual experience of many experienced riders.

The presentation does include a study by Jim Martin that is related to pedalling efficiency. Something is seriously wrong with this bit of work.
- Firstly its only concerned with sprint efforts so not really relevant to most applications
- But more fundamentally it came up with the amazing result that after only 4 days of training a group of non-cyclists was able to out sprint a group of experienced racers. Possible I guess but far more likely there was a flaw in the experiment. The fact that this result was not mentioned gives the impression the author was more concerned with proving a point than doing real science, something that pervades this whole presentation