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Comment by theptip | Hacker News Reader

> A caveat: The cycling in the new study was performed on stationary bikes at a predetermined cadence. It’s possible that the benefits of experience and bike-specific training would be more noticeable on the open road at a freely chosen cadence.

A pretty big caveat. I’m not surprised that cycling on a stationary bike at a fixed cadence has very little room for skill/technique improvements. This invalidates the results vis. real cycling in my book. Gear selection, out-of-saddle technique, etc. Though having said that I’d expect the skill-based component to be much smaller in riding than running as the movement pattern is much more constrained.

Still an interesting result, since it does show that there is a skill-based efficiency gain in running.

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It's interesting because there is a widespread belief (questioned by many, but also still held by many) that pedal stroke at a fixed cadence can be made more efficient by directing the force in more of a circle instead of just pushing down on each side as a beginner does. As you direct the force in a more circular manner, you are supposed to get more efficient. Being clipped in is supposed to allow you to complete the circle by pulling up on the back of the stroke. Conclusive evidence for this has been hard to come by, and I think people now tell commuters and casual cyclists not to worry about it, but many people still believe that the difference is significant for competitive cyclists.

Like you said there are questions of efficiency, but hardly any questions of effectiveness. By clipping in and being able to muscle around the full rotation might burn more calories, but it does allow you to push out more watts. Try climbing a 10%+ incline clipped in vs flats. You might be more tired at the top of the hill clipped in, but with flats you'll likely spin out and be forced to hike your bike. Regarding this study, I don't think form in cycling can be trained on the typical trainer. You'd need a rocker plate and something raises/lowers your fork to perform any of the movement that outdoor riding requires.

>Try climbing a 10%+ incline clipped in vs flats. You might be more tired at the top of the hill clipped in, but with flats you'll likely spin out and be forced to hike your bike.

Doesn't "spinning out" mean your power output is bottlenecked because you can't move your legs fast enough? It only happens when your gear is too low. I don't see how that's possible while climbing, regardless of what pedals you use. I ride with flats, and there's a 10% incline hill not far from where I live. I've climbed it several times (at about walking pace) and never had any problem.

What sort of evidence is needed? Modern power meters can show the complete power phase and torque effectiveness on pedaling strokes. Regardless of efficiency, modern clipless pedals allow for delivering higher maximum power without your feet slipping off.

Only in a bunch sprint.

Otherwise there is no benefit and a lot of downsides in terms of how likely you are to get injured by poor cleat placement or saddle position.

No there are other situations beyond a bunch sprint where you need to briefly put out more power than flat pedals safely allow.

Ah I've often wondered about this when riding! I wear grippy shoes on spiky pedals, but not clipped in (or using a poorly-named clipless system).

Alternating left-right pushes feels very different than trying to maintain a continuous circular motion with quasi-equal force throughout. But unscientifically I can't notice any difference.

Clip ins (“Clipless”) aren’t any more efficient than flats, but will allow a little more power in a sprint.

Clipping in is mostly a cargo-cult among non-pro riders

'Clipless' pedals are so called because the system that preceded them was composed of toe clips and straps. Remove the clips and replace with ski bindings, and voila - clipless pedals!

This is unfortunately a disproven theory.

The evidence to the contrary came in the form of power-meter data from pro cyclists. It shows that professional cyclists instead use their power only in the down stroke of the peddle and have a far less “even” power through the cycle. Their technique is much more similar to a piston engine than a rotary.

Sam Hill. End of discussion

I agree, but then if this is just looking at the physiological effects of training, and not the accoutrements of training, I think you would need to hold the bike constant. Perhaps you can get more efficient at cycling with better frame geometry etc but this is just looking at what the human body alone can do.

I think the problem is that cyclists get more efficient over time on their bike and on the kind of course they are familiar with. In this study, they didn't even have clip-in pedals: "Because not all of the runners were familiar with cycling shoes, all participants cycled in their own running shoes on flat pedals without toe clips or straps."

On a constant-speed training bike without clip-in pedals, a road cyclist will be pretty far out of their element. A lot of the efficiency gain in cycling comes from adding rigidity to the power train between the foot and the road, and from the continuous power application that clip-in pedals and shoes enable.

Although I use clipless pedals on both my road and mountain bikes, most of the research I've seen recently suggests that clipless do not provide any efficiency gain. This video provides links to numerous peer reviewed articles on the topic https://www.youtube.com/watch?v=KUEaN9FKGLE. Of course I'm sure there is research that would suggest otherwise, and I would be interested in seeing counter arguments.

Thanks, that's a great video and I'm going to look through the references. Lots of great points made in the video.

As he acknowledges in the end, a lot of cyclists prefer clip-in pedals just due to stability. In my experience, it's not so much about the upstroke (which to be fair I am surprised was not measured to provide a power benefit), but the knowledge that I will never lose my footing. Without that knowledge, I simply wouldn't apply as much power.

There's seems to be questioning on powering the upstroke, but that has never been "the reason" for foot retention systems. Except for one specific type of cycling-- track cycling, where upstroke IS USED in high acceleration starts like in Match Sprint or short time trials. There are track versions of clipless systems which require a lot more force and twist to get out of.

The main reason for clipless, as I understand it, is for safety and maintaining one's foot on the pedal. When you're pedaling, if you are apply any down-force whatsoever on the upstroke, you're wasting power. So, a trained cyclist will always have their foot practically floating on the upstroke and their foot will drift position as they pedal unless something is keeping it in place.

As a flat pedal rider (and also clips) and someone who has trained fairly extensively in pedaling form here is my 2c. The form of the stroke is to increase the length of the downstroke. So making power transfer happen as early as possible and to maintain it as much as possible at the base. This translates into pushing forward and then down at the beginning and down and back at the end.

This efficiency simply means getting a longer ‘glide’

Its very, very telling when climbing and also trying to attack as when applying extra good form will eek out benefits.

It's a fair point; I'm not sure where you'd draw the line between physiological effects and skill effects and equipment; things like ligament spring-loading sound like they would be subconscious techniques that are also accompanied by physiological adjustments.

And I am sure that you would make a physical adaptation to a sufficiently different frame/fit geometry, though if your fit was "good enough" then upgrading might not incur much change on the physiological level.

There is also no mention of fit changes. Changes in crank length, saddle height, hip angles etc all can have quite considerable effects on efficiency

Double check the crank length. Many of the things you list have to do with bike fit, which I do agree can be wonderous when it comes to feeling comfortable on a bike. But testing various crank lengths I believe didn't have a huge effect on performance. It came down to "whatever you like". I ran a 165mm crank for the longest time, until I realized it was actually a 175mm. But in my head, I always thought the crank to be somehow weird and different. It wasn't! If you're short, maybe a shorter crank length, if you're talk, maybe a longer crank length. Maybe.

I'm pretty sure biking at a fixed cadence outside would have a poor result as well in flat terrain.

At the end of the day I've seen massive improvements in my cycling ability when regularly doing a HIIT bike routine (such as sufferfest for example) on a trainer such as the wahoo kickr.

Honestly, the best performance I ever had in my life was on a 50km race a few months after finishing a 2700 mile MTB race. Safe to say the 2700 had a lot of long, slow miles. That massive base (and recovery afterwards) allowed me to win the 50km race, by 10 minutes, against Cat 1+2 and one pro (who got second). Also everyone else had more than one gears on their bikes.

The Great Divide?

the same can be said for running on a belt all the time. it's OK as substitute for when temperatures fall too far, but certainly worse result than when torturing yourself with real terrain. (alas always better than ending the season before it starts with a broken ankle)

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