Is the "right" pedal stroke over-rated?

[FastforaSlowGuy]

On the drive into work today, I was thinking about all the time, effort and money we all spend trying to perfect the biomechanics of our pedal stroke - to fit it into the "right" box. Press down, scrape back, kick over the top, repeat (or some variation on that). Then I was thinking about golfers and golf swing. I don't golf in any serious way, but guys that do spend a LOT of time on their stroke. In both cases, I get it: form=efficiency. But then there are always those cases of people who do REALLY well with a stroke (golf or pedal) that is just ugly to see and appears to break all the rules.

I mean really, look at these guys:
http://ftw.usatoday.com/2013/06/who-has-the-worst-swing-on-the-pga-tour-according-to-fellow-pros

I'm sure the same is true in cycling. Most top riders have a beautiful pedal stroke and riding style, but there are always some who buck the trend (I think someone here compared Froome to Skelator pushing a shopping cart).

Anyway, it got me wondering whether anyone has done a truly empirical analysis of pedal stroke form and success in competitive cycling. We collect all this data on left-right balance, how "round" a pedal stroke is, etc., but where's the evidence that all of this actually means anything?

[nooneline]

I think there's some uninformed talk about developing a pedal stroke that is round and even. That's misguided - you're always going to be stronger pushing down on the pedal than anywhere else in the stroke.

I figure, as long as your right leg pushing down on the pedal isn't also pushing your left leg up, you're in a good place.

[kgreene10]

I figure, as long as your right leg pushing down on the pedal isn't also pushing your left leg up, you're in a good place.

It makes sense to me that unweighting the upstroke leg is an important step toward efficiency. It will be nice when power meters that can show closer to the full stroke are readily available. I saw some early data from the Pioneer PM that showed a seasoned rider exerting a good amount of downward pressure with the upstroke leg. Many of us may be in for a ride awakening when we can see our results.

[Mark McM]

It makes sense to me that unweighting the upstroke leg is an important step toward efficiency. It will be nice when power meters that can show closer to the full stroke are readily available. I saw some early data from the Pioneer PM that showed a seasoned rider exerting a good amount of downward pressure with the upstroke leg. Many of us may be in for a ride awakening when we can see our results.

To measure efficiency, you need more than just a power meter - you also need something to measure metabolic energy expenditure (this is usually done by measuring inhaled and exhaled gasses).

Several studies have been done to try to measure efficiency changes with different pedaling techniques. These studies have shown that some techniques can change maximal power, or time to fatigue, but none have shown much change in overall metabolic efficiency.

[FastforaSlowGuy]

To measure efficiency, you need more than just a power meter - you also need something to measure metabolic energy expenditure (this is usually done by measuring inhaled and exhaled gasses).

Several studies have been done to try to measure efficiency changes with different pedaling techniques. These studies have shown that some techniques can change maximal power, or time to fatigue, but none have shown much change in overall metabolic efficiency.

I guess this is closer to what I'm getting at. Because it may sound better to have equal power from each leg (to pick one metric), but does it actually MATTER from an outcome perspective? Before we all get bent out of shape staring at our left-right power, perhaps we need to figure out whether there's any evidence whether 50%-50% is any better than 42%-58%.

Put another way: if someone's goal is to win bike races, do we have real evidence that all these metrics we stare at actually contribute to that goal?

[Bob Ross]

Put another way: if someone's goal is to win bike races, do we have real evidence that all these metrics we stare at actually contribute to that goal?

This reminds me a bit about the discussions/arguments that go on around "proper technique" [sic] when playing a musical instrument.

There's a crap-ton of pedagogy that defines what "proper technique" is on any particular instrument. I'm a bass player, so most of my familiarity is with that instrument. There are bass players that I absolutely cannot bear to watch, because their technique is so dramatically contrary to what the accepted proper technique is.

But it turns out that not watching them is a good idea, because what's the goal of playing a bass? Making music. I close my eyes, and they're some of the finest bassists on the planet. Open them, horrified; close them, awed.

So it all gets back to What Is The Goal? And yeah, that's not always clearly defined when somebody tells you "You're not pedaling that bicycle correctly."

[Dead Man]

How about watching David Fray play piano... :help:

I have a beautiful golf swing. To watch me swing a long iron, perfectly sweeping the grass and coming to a smooth, clean finish pose like a slung long-bow.... you'd think I could play.

Unfortunately for me, I'm just a really good imitator... my long game is @#$ing horrible.

I remember trying to train myself to use "circular" peddling technique when I started getting serious on the bike. Never took. Instead, I go to a "scissor" stroke when spinning up... on the track you really have to do this. But trying to engage all these other little, weak, non-strength muscles in the hopes of taking some strain off the major up/down muscle groups.... I just don't think it pans out in reality. It's always felt like I'm tiring out faster, not conserving energy.

[carpediemracing]

I think there's a point to doing a reasonably efficient pedal stroke. I've watched less experienced racers make huge efforts but not go very fast, usually when attacking (watch any Cat 5 race at the bell and you'll see what I'm talking about). They're fine in the field sitting on wheels but when they get out of the saddle they seem to double or triple their output and go only 1-2 mph faster. I think those riders can (and probably will) radically improve their return on energy expended.

Likewise if you watch a pro (or ex-pro) pedal, there's an element of efficiency there. They can be out of shape, heavy, whatever, and still be pretty efficient in terms of not much wasted energy.

I'm not a pro but over the years I've become more efficient. A teammate had a helmet cam in a race where I started cramping almost at the start of the race. I kept thinking "just another lap" for 45 minutes or something nutty like that. I finally started cramping everything and stopped. My teammate caught his on his clip. When I watched it it looks like I just stopped. There's no sign that I'm cramping all over the place - hamstrings, calves, quads. The clip is here (https://www.youtube.com/watch?v=gDehYNryPUc). At 44:40 he's looking for me, thinking of leading me out. He finds me at about 45:35. At about 46:20 he rolls by me, wanting to lead me out. I never got on his wheel, I was absolutely maxed out at 23 mph or whatever.

I'm realistically a better violin player than a bike racer. One of the reasons is I apparently was taught good form. This gave me an efficient base, if you will, from which I could play the violin. Eliminate some of the advantages that basic form gave me and I'd lose this aspect or that aspect of the violin. Bow hold, holding the violin with the chin/neck instead of with the arm, etc. I can see how my tone or speed or intonation would deteriorate if I had poor form.

I think that a talented person, music or bike or whatever, can succeed in spite of their form drawbacks. For the rest of us good form is a way to optimize what limited talent we have.

[Black Dog]

^..This..^

It really comes down to your whole body. People who look very fluid on the bike are not wasting any effort on moving any part of their body that is no directly involved in making the bike go forward, especially when they are near the red line. In racing you need a good poker face to hide the pain and just as much a poker body to do the same. Racing teaches riders to not waste even the smallest amount of energy unless you have to. Keeping the upper and body relaxed and fluid saves a lot of energy and keeps the oxygen moving to your legs. The winner is of a race is not the guy or girl who was strongest on the start line, it the person who is strongest on the finish line. Efficiency is king.

[sandyrs]

People tell me I have a smooth pedal stroke and I'm slow as hell, so...

[Black Dog]

People tell me I have a smooth pedal stroke and I'm slow as hell, so...

Smooth does not mean fast, it generally means faster than not smooth all else being equal... :)

[Bob Ross]

Smooth does not mean fast, it generally means faster than not smooth all else being equal... :)

Well...since you can't be really fast -- or really fast and safe -- without being smooth, it can be a handy aphorism to skip all the caveats and middlemen by just saying "Smooth Is Fast"

[Ti Designs]

Several studies have been done to try to measure efficiency changes with different pedaling techniques.

Do any of these studies change pedaling technique using the standard motor leaning process, or do they assume that people can change it just by thinking about how they pedal? The best I've seen so far has been 45 minutes of instruction before testing. So they get into the cognitive portion of the leaning process and just skip the rest - yeh, I can't see how that wouldn't work...

Training for cycling has little to do with metabolic efficiency, it has to do with the interface between human and machine - how to best use your body to get somewhere. You probably know how to walk and how to swim - which one is better? That depends on conditions, on land walking works best. In a few inches of water, walking still wins. When the water gets over your head you probably want to switch to swimming. Different ways for different conditions - it's not that complicated. When they take it into a lab, that common sense goes out the window and they try to find the one best way to pedal or the most efficient cadence.

I've worked with sprinters who can generate huge amounts of power for short bursts, I've worked with time trial specialists who can how a narrow power band for an hour, I've worked with climbers who have amazing power to weight ratios, none of these people pedal the same, but there are some things in common in their training programs. The concept of not letting what you've learned by standing or walking waste energy on the bike keeps coming up. When you stand or walk you have weight on your feet - it's just a normal state. Keeping weight on the foot as it comes up the back of the pedal stroke follows - it's what you've learned elsewhere. As your effort increases, so does that force. I'm working with a number of riders using the Pioneer power meters, those long, down facing vectors don't lie. When I first start working on hip flexors people think they're going to climb better 'cause they have this extra muscle group to use. Then reality sets in - you might be able to pedal for 2 minutes just using that muscle, in a very easy gear. There's just no wattage there. So why use it? There's something called reciprocal inhibition, the body doesn't fire opposing muscle groups. So in just getting the hip flexor active you are shutting down the muscle that pushes down.

[Dead Man]

Here's my essentially unapplicable, off-topic, but related-sounding post of the day...

In competitive shooting, we have an expression slow is smooth and smooth is fast. In summary, having good form means having an economy of motion that will be overall efficient, and efficiency is more important than speed in training, because efficiency begets speed.

Train correctly; speed will follow.

[jr59]

That's the question. What is correct? Because correct for one person,may very well not be correct for the next.

[binxnyrwarrsoul]

I've pedaled squares since the early eighties, highly doubt "rounding" my spin is gonna make me any faster. Can't possibly make me any slower.

[MattTuck]

The best I ever felt on the bike was when I was light and riding a lot.

If you get the position within tolerances, I think efficiency takes care of itself over time. Yes, there are things you can do to train yourself to be more efficient, but just getting miles in your legs really helps.

As for the question above, about whether 42/58 is really worse than 50/50... I guess the question is, can you get to 45/58 or 50/58 without too much work, and that is probably a net positive for your riding.

As is probably obvious to people that ride, if you rely on one side more than the other, it gets stronger and more developed, which allows it to be depended on more and more. It is a feedback cycle that is not ideal. Investing the time/effort to develop the weaker leg (whether that is strength, neuromuscular, flexibility, etc.) is a way to get out of that feedback cycle.

[wallymann]

ive asked this question before. owned a set of power-cranks to rehab an injured/ill-behaved leg and got me curious about the value of a perfectly round pedal-stroke (i.e., with very active scraping/pull-up/push-over-top phases).

among folks with alot of exercise-physiology and coaching experience, the consensus was that there are limited returns beyond the basics of a sound, even pedal-stroke. "good" is good enough as the best cyclist simply have the best push on the downstroke and adequately get out of the way everywhere else. any more is a waste of time and aerobic capacity.

on a closely related topic, the best cyclist are also the most bio-mechanically efficient pedalers (bio-mechanically efficient pedal-stroke with souplesse (http://www.souplessebikes.com/souplesse/) is somewhat different from having a round pedal-stroke).

[unterhausen]

hey, if you train yourself to pull up, it's a lot easier to ride one-legged after your knee blows out. A couple of years ago, I rode 20 miles that way -- I don't recommend it. More recently, I got a cramp in my right leg at the end of a brevet, so I one-legged it up the final hill. There was a crowd at the finish and a number of people were puzzled as to what I was up to with that.

[milkbaby]

I don't get it; aren't we constrained to pedaling in circles because the cranks move in a circle?

But seriously, as long as I'm not getting overuse injuries on the bike, I'm happy. :)

[Ti Designs]

I don't get it; aren't we constrained to pedaling in circles because the cranks move in a circle?

That's how people get the impression that riding a bike is natural or has no learned skill. The pedal does control the movement, so to most the best pedal stoke looks just like the worst pedal stroke.

The pedals move around in a circle, riders see this and assume they are pushing the pedals around in a circle. Not just the idiots, there was a study at harvard where they mounted strain gauge pedals on a bike on a computrainer. The strain gauges measured force, cadence measured distance, and they made the assumption that people always push in the direction the pedals are moving in, because that's the way they move. They couldn't explain why calculated wattage from the pedals and measured wattage at the rear wheel was different from person to person.

A while back I found out that there are points within the pedal stroke where the body has very little ability to generate torque. I built a machine to test this, but it turns out a number of the power meter companies knew about this all along. Pioneer has what I consider the best training tool going, a power meter that shows force vectors every 30 degrees. The problem is it's a measuring device, it tells the truth. It shows what the rider is really doing at the pedals, and it's insulting to some people if you tell them they don't know how to pedal a bike (I'm the leading expert in insulting people this way). Stages' marketing department is better than Pioneer's, they knew about the dead spots in the pedal stroke, they just don't tell anyone. They have a very high sampling rate, but they round the output so the user never sees points within a single pedal stroke which generate nothing.


As for this concept of a round pedal stroke, a pedal stroke is made up of force vectors (muscles being used to push the pedal in some direction). A vector is made up of two parts, direction and magnitude. A perfect pedal stroke would always have the direction be tangential to the crank arm. You can argue this point if you want, but the efficiency coefficient is SIN(offset angle)... Magnitude is different. I can push 1100 pounds with my glutes, 30 pound with my hip flexors. Saying the magnitude should always be the same means I would need to limit the larger muscle groups to what the smaller ones produce - that's just plain stupid. In fact, when more torque is needed, the smaller muscle groups are shut down in favor of the larger ones.

[wallymann]

also consider there is a "fuel cost" to power various muscle groups one may/not want to recruit for the pedalstroke and a "time cost" to train those same potential contributors. one could train for years to improve their wee-little hip flexors, but as you suggest there's a limit to potential contribution to forward motion.

train the big pushers as best you can to go fast, train the little ones "good enough" to get out of the way, and ride alot so you get efficient.

...I can push 1100 pounds with my glutes, 30 pound with my hip flexors. Saying the magnitude should always be the same means I would need to limit the larger muscle groups to what the smaller ones produce - that's just plain stupid. In fact, when more torque is needed, the smaller muscle groups are shut down in favor of the larger ones....

[Pastashop]

I try to pedal as efficiently as my body will naturally let me. I discover the most efficient "style" of pedaling at the end of a long ride, where the body automatically tries to conserve energy, just to ensure I make it back home. :-)

Aside from that, it's all about how you express yourself through your cycling. Or anything you do for recreation, really.

[HillDancer]

I recently moved to flat pedals and have been researching alternative pedaling techniques. I came across this interesting video about flats vs clipless https://www.youtube.com/watch?v=CNedIJBZpgM Note pedaling with flats, where utilizing the upstroke is limited, oxygen needs were less for this one rider.

[dnc]

Anyway, it got me wondering whether anyone has done a truly empirical analysis of pedal stroke form and success in competitive cycling. We collect all this data on left-right balance, how "round" a pedal stroke is, etc., but where's the evidence that all of this actually means anything?


I spent 30 years experimenting and perfecting techniques for flat road riding and this is what I found. There are four different seated pedalling techniques. Starting with semi circular which can supply sustainable maximal power for time trials, it applies maximal force over 180 deg. from 11 to 5 o'c, (90 deg. is fully tangential). This is how it looks and this man is still regarded as the world's greatest TT rider,
https://www.youtube.com/watch?v=7hh2DcgpnkU.
Next is mashing which can supply maximal unsustainable power for use in seated sprinting or other acceleration purposes. It applies maximal force over 120 deg. (30 deg. is fully tangential). Circular is the third technique that needs concentration over the entire 360 deg. It is useful in the lesser demanding situations (group riding etc.). Lastly you have free style for those who don't believe in concentrating on their pedalling.

[slidey]

Whoa! I was just thinking of this when I read the above post by Black Dog. This is the exact saying my Sifu says all the time.

Slow makes it smooth, smooth makes it fast

:hello:
In competitive shooting, we have an expression slow is smooth and smooth is fast. In summary, having good form means having an economy of motion that will be overall efficient, and efficiency is more important than speed in training, because efficiency begets speed.

Train correctly; speed will follow.

[Black Dog]

Do any of these studies change pedaling technique using the standard motor leaning process, or do they assume that people can change it just by thinking about how they pedal? The best I've seen so far has been 45 minutes of instruction before testing. So they get into the cognitive portion of the leaning process and just skip the rest - yeh, I can't see how that wouldn't work...

Training for cycling has little to do with metabolic efficiency, it has to do with the interface between human and machine - how to best use your body to get somewhere. You probably know how to walk and how to swim - which one is better? That depends on conditions, on land walking works best. In a few inches of water, walking still wins. When the water gets over your head you probably want to switch to swimming. Different ways for different conditions - it's not that complicated. When they take it into a lab, that common sense goes out the window and they try to find the one best way to pedal or the most efficient cadence.

I've worked with sprinters who can generate huge amounts of power for short bursts, I've worked with time trial specialists who can how a narrow power band for an hour, I've worked with climbers who have amazing power to weight ratios, none of these people pedal the same, but there are some things in common in their training programs. The concept of not letting what you've learned by standing or walking waste energy on the bike keeps coming up. When you stand or walk you have weight on your feet - it's just a normal state. Keeping weight on the foot as it comes up the back of the pedal stroke follows - it's what you've learned elsewhere. As your effort increases, so does that force. I'm working with a number of riders using the Pioneer power meters, those long, down facing vectors don't lie. When I first start working on hip flexors people think they're going to climb better 'cause they have this extra muscle group to use. Then reality sets in - you might be able to pedal for 2 minutes just using that muscle, in a very easy gear. There's just no wattage there. So why use it? There's something called reciprocal inhibition, the body doesn't fire opposing muscle groups. So in just getting the hip flexor active you are shutting down the muscle that pushes down.


And there it is. Ti, you have nailed it perfectly. It is not about perfect circles but developing a technique that allows you to remove the load from the dead leg by adding a bit of lift from the hip flexors. It takes a good amount to time to convert this technique from being a conscious effort to muscle memory (really a skill stored in the motor cortex). Just like learning to walk, run, swim etc... Riding a bike is not natural, we just poorly adapt motions from other learned movements to the bike. All the studies that show high end cyclists putting out amazing power while not pedalling nice circles is not an argument against technique it is an argument for it. I bet that these riders are adding lift the the dead leg which allows a lot more down force, for a longer time to fatigue. With vector based power meters we can easily measure this.

BTW, Cross country skiing is a great activity to help recruit the use of hip flexors and build their capacity which is easily transferred to the bike.

[bironi]

Must be too much snow on the roads back there still to dive down this rabbit hole again.:beer:

[Mark McM]

Do any of these studies change pedaling technique using the standard motor leaning process, or do they assume that people can change it just by thinking about how they pedal? The best I've seen so far has been 45 minutes of instruction before testing. So they get into the cognitive portion of the leaning process and just skip the rest - yeh, I can't see how that wouldn't work....

Yes, some did. This study had a limited amount of pedal stroke coaching:

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

This study had gave half the participants 4 one hour coaching sessions on a specific pedaling technique (called "pose" cycling):

http://www.ncbi.nlm.nih.gov/pubmed/21127899



I've worked with sprinters who can generate huge amounts of power for short bursts, I've worked with time trial specialists who can how a narrow power band for an hour, I've worked with climbers who have amazing power to weight ratios, none of these people pedal the same, but there are some things in common in their training programs. The concept of not letting what you've learned by standing or walking waste energy on the bike keeps coming up. When you stand or walk you have weight on your feet - it's just a normal state. Keeping weight on the foot as it comes up the back of the pedal stroke follows - it's what you've learned elsewhere. As your effort increases, so does that force. I'm working with a number of riders using the Pioneer power meters, those long, down facing vectors don't lie. When I first start working on hip flexors people think they're going to climb better 'cause they have this extra muscle group to use. Then reality sets in - you might be able to pedal for 2 minutes just using that muscle, in a very easy gear. There's just no wattage there. So why use it? There's something called reciprocal inhibition, the body doesn't fire opposing muscle groups. So in just getting the hip flexor active you are shutting down the muscle that pushes down.

This actually agrees with other research, comparing the pedal forces of local amateur racers vs. elite national racers. The elite racers don't produce more even power around the whole circle - they don't push forward, pull back or pull up harder - than the amateurs; they primarily just push down harder. The elite racer's pedal forces were actually less balanced between the rising and falling pedals than the amateurs. The elites pulled up on the pedals only a little bit more than the amateurs, but they pushed down on the pedals a lot more.

Using your hip flexors to unweight the rising pedal is effective to some amount, but it only goes so far. Trying to pull up harder doesn't result in more power.

[Black Dog]

This actually agrees with other research, comparing the pedal forces of local amateur racers vs. elite national racers. The elite racers don't produce more even power around the whole circle - they don't push forward, pull back or pull up harder - than the amateurs; they primarily just push down harder. The elite racer's pedal forces were actually less balanced between the rising and falling pedals than the amateurs. The elites pulled up on the pedals only a little bit more than the amateurs, but they pushed down on the pedals a lot more.

Using your hip flexors to unweight the rising pedal is effective to some amount, but it only goes so far. Trying to pull up harder doesn't result in more power.

This is true but lifting the leg is not about adding power from the lift, it is about reducing the load that the pushing leg has to overcome. This allows more power to be generated. That is why the elite riders push harder, they are not being as inhibited by the mass of the dead leg. This reduces fatigue and allows for greater power generation on top of the extra power that is produced from the lack of dead leg resistance during the pedal stroke. Also, extra training generally makes them more powerful regardless of any other factor at play.

[leftyfreak]

This is true but lifting the leg is not about adding power from the lift, it is about reducing the load that the pushing leg has to overcome. This allows more power to be generated. That is why the elite riders push harder, they are not being as inhibited by the mass of the dead leg. This reduces fatigue and allows for greater power generation on top of the extra power that is produced from the lack of dead leg resistance during the pedal stroke. Also, extra training generally makes them more powerful regardless of any other factor at play.

It's all about efficiency in two ways.

First, if the right leg is on the upstroke, the activation of the hip flexor unloads the right pedal, reducing the load on the left glute, as has been mentioned.

Second, as Ti Designs has alluded to, the concept of reciprocal inhibition comes to play. The activation of the right hip flexor on the upstroke also causes the right glute to shut down. So this also means that the right glute is getting a chance to recover for a period of time during the pedal circle, rather than being under tension the whole time.

Fundamentally, it's about learning to use your muscles in the region of the pedal stroke where they will be most effective. It's not about some mythical "round" pedaling technique.

[Ti Designs]

Having done a bit of research myself, the one conclusion I keep returning to is that people make a lot of assumptions about what they're doing at the pedals - and a lot of those assumptions are wrong. Challenging those assumptions will result in one of three outcomes. The common one is anger and outrage - how can anyone not know how to pedal a bike? I then often get told how long they've been riding... The less common outcome is to entertain this idea that learning how to pedal might just be a good idea. The third outcome is that I'm wrong, so I built a test rig...

https://drive.google.com/file/d/0BzPaPufWMAPLY1J0dE5VS2gwQjQ/view?usp=sharing

[MattTuck]

Having done a bit of research myself, the one conclusion I keep returning to is that people make a lot of assumptions about what they're doing at the pedals - and a lot of those assumptions are wrong. Challenging those assumptions will result in one of three outcomes. The common one is anger and outrage - how can anyone not know how to pedal a bike? I then often get told how long they've been riding... The less common outcome is to entertain this idea that learning how to pedal might just be a good idea. The third outcome is that I'm wrong, so I built a test rig...

https://drive.google.com/file/d/0BzPaPufWMAPLY1J0dE5VS2gwQjQ/view?usp=sharing

That rig is impressive.

[Dead Man]

Having done a bit of research myself, the one conclusion I keep returning to is that people make a lot of assumptions about what they're doing at the pedals - and a lot of those assumptions are wrong. Challenging those assumptions will result in one of three outcomes. The common one is anger and outrage - how can anyone not know how to pedal a bike? I then often get told how long they've been riding... The less common outcome is to entertain this idea that learning how to pedal might just be a good idea. The third outcome is that I'm wrong, so I built a test rig...

https://drive.google.com/file/d/0BzPaPufWMAPLY1J0dE5VS2gwQjQ/view?usp=sharing

You mention dead spots...

I started riding the trainer this winter.. first time ever, and it's been an awkward thing for me.. but one thing I notice is that it's very easy for me to get little voids in my pedal stroke that go clackclack softly when the chain goes tight again. I've never felt anything like it in my outside on-the-road pedal stroke..... but then, a couple days ago, I had a long-story-short wheel catastrophe that had me running a 12-25 cassette on a TT, when I'm already not a TTers and used to running an 11-28 for my preferred hills... and I found that the significantly more gradual gearing mixed with TT mashing was also inducing these same clackclack pedal voids I experienced recently on the trainer.

What's up with that? Suddenly I feel like I need to start studying pedal stroke efficiency

[Uncle Jam's Army]

Having done a bit of research myself, the one conclusion I keep returning to is that people make a lot of assumptions about what they're doing at the pedals - and a lot of those assumptions are wrong. Challenging those assumptions will result in one of three outcomes. The common one is anger and outrage - how can anyone not know how to pedal a bike? I then often get told how long they've been riding... The less common outcome is to entertain this idea that learning how to pedal might just be a good idea. The third outcome is that I'm wrong, so I built a test rig...

https://drive.google.com/file/d/0BzPaPufWMAPLY1J0dE5VS2gwQjQ/view?usp=sharing

Ed, your posts and videos have helped me think long and hard about my pedal stroke and how to achieve efficiency with it. I still haven't figured it all out, but I enjoy the process of trying to do so. Many thanks.

[1centaur]

I like that rig, TiD.

One of the interesting things about unweighting a leg vs. lifting it is that the more unweighted the leg the easier it is for the power leg to push the pedal up into the unweighted leg. At some point unweighting becomes pulling just so the unweighted leg can stay ahead of the chasing power leg.

This is not to say that the lifting muscles have a lot of power, but ultimately I think those puny muscles are better trained to pull a little than just to unweight.

Single leg drills miss this point because there is no power leg chasing the pulling leg, but at the same time they don't just unweight because then the stroke would not continue.

[leftyfreak]

Enough comments about the rig. Nice hat! I can't believe I've never seen it before.

So, when do I get a turn on that rig/torture device?

[Ti Designs]

I started riding the trainer this winter.. first time ever, and it's been an awkward thing for me.. but one thing I notice is that it's very easy for me to get little voids in my pedal stroke that go clackclack softly when the chain goes tight again.

Do you know what detonation or knock is when talking about a car engine? It's ignition (well, really thermal expansion) of the fuel mixture before the piston reaches top dead center. It's a serious problem because the expansion while the piston is still going up subtracts energy from the system, and the pressure at the cylinder head spikes. On a bike, starting to push down before TDC (12:00) is very much like that. It slows the crank going over the top and increases the tension of the patellar tendon. The deceleration causes the chain to lose tension, getting over the top regains tension, that's what you hear. I'm doing a video series about destructive forces in sport for a local hospital that covers this.

[Mark McM]

Do you know what detonation or knock is when talking about a car engine? It's ignition (well, really thermal expansion) of the fuel mixture before the piston reaches top dead center.

Well, technically, combustion/gas expansion always starts before TDC - knock happens when parts of the fuel/air mixture explodes/expands ahead of the normal combustion pressure front.

But I get your point - muscle contractions that happen too soon (or continue too late) in the pedal stroke are detrimental to power and efficiency.

[Mark McM]

One of the interesting things about unweighting a leg vs. lifting it is that the more unweighted the leg the easier it is for the power leg to push the pedal up into the unweighted leg. At some point unweighting becomes pulling just so the unweighted leg can stay ahead of the chasing power leg.

This is not to say that the lifting muscles have a lot of power, but ultimately I think those puny muscles are better trained to pull a little than just to unweight.

For short duration efforts, this is definitely true. But aerobic efforts are limited more by the ability to circulate blood/oxygen to the muscles (and carry away waste products) than the by the total amount of muscle available, so trying to pull up too much can be a matter of robbing Peter to pay Paul. Any blood/oxygen used trying to pull up is stolen from the larger and more effective muscles pushing down.