Bouncing at High Revs

[bobscott]

Inspired by forum discussions, especially those from Dave Kirk and Ti Designs, I have been working on my pedal stroke this winter.

Some how I have gotten myself to a place where I bounce alot at high revs. I used to start bouncing at about 125 rpm but recently it seems I am pretty bouncy at 95 rpms. I have been doing spin-ups about 3 times per week, saome one legged spin-ups, and working on the bottom and top of my stroke.

It is also not clear to me what is leading to the bounce. First I though it was pushing down at the bottom of the stroke but that doesn't seem to be the case. It doesn't seem to arise from pulling across the top of the stroke either.

My trainer bike has an old San Marco Regal suspension saddle, the one made in conjunction with Pirelli. I am guessing this is a contributor and I should go to a conventional saddle..but I used to be able to spin on it.

Thoughts, suggestions and usual forum wisdom would be appreciated.
bobscott

[dookie]

saddle height?

more time on a fixed gear and/or rollers!

[scottsmith12]

aka buttbob....

Everyone has a little at different ranges. The key is to narrow it down so there is little. I ride fixed a lot in the winter. At the beginning of the winter the range is from about 125 to 145rpm. Funny how it smooths right out after you get going faster. Now it's ranging from 135 to 145 and it's less noticeable all around.

And yes, saddle height plays a big part.

I had a world class sprinter tell me one time that he doesn't worry about going around. It's more about moving your feet in a shuffle back and forth. He says the crank takes care of the up and down part.

Ahh gees.... I just noticed your name is Bob. I meant bob as bobbing... :D

[dekindy]

The High Intensity Training program that I followed recommended using a 39/27 gear. First drill was to start at 50 rpm and increase 5 rpm every minute and max out at 120. This takes 14 minutes. The second drill was starting at 70 rpm and increasing 5 rpm every 15 seconds and maxing out at 130 initially and eventually work up to 150 rpm in future weeks. Bouncing reduced gradually as the weeks progressed.

That and one-legged drills using the same gear and harder gears has increased my cadence and smoothed my pedal stroke. At least it feels like it has. I will see if that translates to more power as I try harder efforts on training rides this Spring.

[regularguy412]

I had a world class sprinter tell me one time that he doesn't worry about going around. It's more about moving your feet in a shuffle back and forth. He says the crank takes care of the up and down part.

Ahh gees.... I just noticed your name is Bob. I meant bob as bobbing... :D

I'm certainly not a world class sprinter, but the bold above is how I try to perceive it. I try to move my feet in an elliptical motion, as in: forward and back through the stroke,, where the focii of the ellipse are at the 3 o'clock and 9 o'clock positions.

Mike in AR:beer:

[LesMiner]

Another analogy is scrapping mud off your shoe. I find it seems at higher rpm I am lifting more as the pedal is at the rear position. Also I feel I am pushing a little forward on the saddle.

[MIN]

Aside from poor form, a saddle which is too high will contribute to the bouncing... for me even 3mm in saddle height makes a difference. I use a fixed gear on the rollers - when I first started, it was difficult to maintain 120 rpm without bouncing but I can hit close to 200 revs for short bursts. You have to really think about foot position and alignment relative to the pedal and the imaginary fore-aft axis. After a long interval hi-rev training sessions, my shins are often sore due to its work in stabilizing the foot.

[giordana93]

+1 on saddle height. also cleat placement: cleats mounted rearward tend to block the ankle a bit, which can be a good thing, but it takes the suppleness out of the joint. I would NOT experiment with cleat placement if you have no other issues other than the bouncing, however. it could also be saddle fore-aft, as your butt is naturally trying to move to the place it wants to be for the high revs, which may or may not correspond to where the sweet spot of the saddle is. but 95 is a pretty low cadence to start bouncing. could well be too high, as you're "reaching" to get to the bottom of the stroke.

[Bob Ross]

I had a world class sprinter tell me one time that he doesn't worry about going around. It's more about moving your feet in a shuffle back and forth. He says the crank takes care of the up and down part.
I try to move my feet in an elliptical motion, as in: forward and back through the stroke,, where the focii of the ellipse are at the 3 o'clock and 9 o'clock positions.

Yep, I got that same advice from a bike fitter in Tucson, and that usually works like a charm if I start to bounce at high cadences.

Actually, some of the best advice I got regarding this was "if you're bouncing, upshift." Folks get so hung up on maintaining a specific target cadence that they forget that there's a range of cadences that will still meet almost any objective. If you're bouncing at a high cadence, you're probably in too low a gear.

[Viper]

Lay off the Guinness.

[paczki]

Have you tried doing the one-legged drills both sides very slowly on very little resistance and then spinning up? It does wonders for loosening the legs. If you're thinking about the pedal stroke too much when you're reving up that can induce tension.

[dekindy]

The training book I have, High Intensity Training For Cyclists, says that saddle height, leg strength, and aerobic and anaerobic fitness have nothing to do with bouncing at high cadence.

The muscles are simply not receiving an impulse to stop pushing down soon enough. A leg that is still pushing down at the bottom of the stroke while the other pedal is coming up forces the rider off the seat.

So they are suggesting that you are still pushing down at the bottom of your pedal stroke.

High cadence drills that I have already outlined in my previous reply will improve pedal stroke. In their 12-week program this is the first drill for every single session of the program. They think it is that important a skill. It took me several weeks before I started seeing improvement.

One-legged pedaling drills will help your pedal stroke also.

[dookie]

A leg that is still pushing down at the bottom of the stroke while the other pedal is coming up forces the rider off the seat.

possibly exaggerated by a too low saddle?

[dekindy]

possibly exaggerated by a too low saddle?

Not according to Arnie Baker, MD, author of High Intensity Training For Cyclists. I guess you can try it and see. I was already fitted when I did this program so I can't comment personally.

[Ti Designs]

Hard to talk about bouncing in the saddle without looking at the whole fit on the bike. The differences at slower and faster cadence would indicate that there's something else changing as well. Most people don't really notice how the get lower as the rpms get higher. This goes against the idea that the hip has a limited range of motion, getting lower is closing in on it's limits. I often tell my riders to sit up and pedal the bike - try one legged drills (slowly) on the tops of the bars, then try them (still slowly) in the drops - I'll bet it's way harder in the drops.

This is the kind of thing where I would have the rider set up a big mirror, or better yet a video camera at the side of the bike so they can watch themselves real time. Then, everything happens at low speed - you don't learn at high speed. The one legged pedal stroke drill is the key, but only when done right. First, a super easy gear. You're not powering the bike, you're teaching your body that there's a circle you have to trace. Your foot should go in that circle, even if not attached to the pedal. One minute right side, one minute left, slowly so you can't tell by the sound that you're only clipped in with one foot. Wax on right hand, wax off left, don't forget to breath - opps, wrong movie! After the minute on each side, clip in with both feet, pedal exactly the same way you did with just one foot, but bring up the RPMs until you start to bounce. It helps to tighten the abs and pull in slightly on the bars, which will stabalize your hips in the saddle. Each time you do this you should feel yourself get just a little bit smoother.

Next you learn paint fence...

[bobscott]

As always, thanks to everyone for the input...lots of kernels of wisdom here. The forum is such a valuable resource.

I am still in the analysis phase of this information. I'll keep you posted on my progress.

I know that TiDesigns teaches a night class in Boston but wonder if he had thought of or done some sort of week end "camp" for us out of towners.

On that note I'll "bounce on down the road".

bobscott

[capybaras]

I know that TiDesigns teaches a night class in Boston but wonder if he had thought of or done some sort of week end "camp" for us out of towners.

bobscott

Great idea! :banana:

[Ti Designs]

I know that TiDesigns teaches a night class in Boston but wonder if he had thought of or done some sort of week end "camp" for us out of towners.


I've played with the idea, both in the DC area and with a club near Saratoga after doing a fitting on a girl from there. In season it gets a bit harder because of work, but given a group, a place to stay and a place for a trainer workout or two, why not?

[bobscott]

I mentioned in my first post that I was using a SSM/Pirelli rubber bumper suspension version of the Regal saddle. I ebayed a normal Regal and I am now bounce-free up to about 140 rpm where I get a small amount of bounce.

Thanks again to all for the input which was useful beyond my bounce problem.

bobscott

[zap]

snipped


The muscles are simply not receiving an impulse to stop pushing down soon enough. A leg that is still pushing down at the bottom of the stroke while the other pedal is coming up forces the rider off the seat.



If I decide to spin (which I rarely do), I switch off the quads. I focus on the hamstrings and a few other smaller muscles and go, maybe up to 130. It works for me and it all feels different than real pedaling but my ass is not bouncing off my saddle.

Ti, I think you would have a few places to stay in the MD 'burps of D.C. Plus good marketing options.

[RPS]

It is also not clear to me what is leading to the bounce. First I though it was pushing down at the bottom of the stroke but that doesn't seem to be the case. It doesn't seem to arise from pulling across the top of the stroke either.Playing Devil’s advocate:

You are correct in that the primary cause of bouncing is not pushing down on the pedal at the bottom – or pulling across the top either. If this was the case, we’d all bounce more at lower cadences when we normally push down with greater force; and that’s clearly not the case.

Many have suggested great ideas on how to learn how to mitigate bouncing, but none seem to address your question of what leads to bouncing.

IMHO the root cause is quite simple yet too complicated for most of us to analyze. Fortunately through experience we can learn to alter our pedaling to “offset” the main reason we bounce in the first place. When people talk about smoothing out the pedal stroke to prevent bouncing what it means to me is learning how to create opposing forces that will help cancel out the bouncing forces. And this should raise the question of whether this creates “smoothness” efficiency but “power” inefficiency when applied at other cadences.

Because of this I don’t see an inherent advantage to learning how to spin “smoothly” at 120 RPM unless one wants to ride at 120 RPM. If a rider plans to ride at a lower non-bounce cadence of say 80 to 100 RPM, I can see how “altering” one’s pedal stroke to prevent bouncing as if we were riding at a higher cadence could do more harm than good.

[Ti Designs]

Because of this I don’t see an inherent advantage to learning how to spin “smoothly” at 120 RPM unless one wants to ride at 120 RPM. If a rider plans to ride at a lower non-bounce cadence of say 80 to 100 RPM, I can see how “altering” one’s pedal stroke to prevent bouncing as if we were riding at a higher cadence could do more harm than good.

There are two elements working here, muscles moving the pedals in the right direction and timing. I can't see any down side to using the right muscles in pushing on the pedal in the right direction. Timing has limitations as any other feedback loop will have. I can't think of any cases where timing can't be slowed down, it's speeding up beyond what the feedback loop can handle that's a problem.

As for the gains to be had at any RPM, it's hard to make the distinction between power, efficiency and comfort. The human body produces a depressingly low number of watts, any efficiency gained is a gain in power. What's more, any strength gained after is multiplied by the gain in efficiency. But it's really the relationship between power and comfort that most people don't get. Nobody bounces straight up and down, one hip goes up, the other comes down. The SI joint moves, takes the spine with it. The muscles of the lower back which protect the spine fire with each forced adjustment, which is why lots of riders get sore lower backs.

[RPS]

There are two elements working here, muscles moving the pedals in the right direction and timing. I can't see any down side to using the right muscles in pushing on the pedal in the right direction. Timing has limitations as any other feedback loop will have. I can't think of any cases where timing can't be slowed down, it's speeding up beyond what the feedback loop can handle that's a problem.I don’t see these as the primary reason riders bounce as their cadence increases.

If the rider learns to “introduce” inefficient pedaling forces solely to mitigate bouncing, how can that be a good thing at slower cadences where bounce isn’t an issue anyway?

[bobscott]

For what its worth, Mark Cavendish attributed his recent Milan-San Remo win to leg speed he developed and maintains by track riding.

See: http://www.velonews.com/article/89481/cavendish-i-wanted-to-prove-i-am-a-great-rider

bobscott

[bobscott]

I'm all in favor of devil's advocacy especially since I would love to hear more discussion of this subject.

Still, since the bounce disappeared with a fixed position rather than a suspension saddle, possibly this is not the best example to use for an hypothesis of the nature of the efficiency of a smooth pedal stroke.

That said, I would have though that the suspension saddle would have made the pedal stroke source of the bounce more obvious but it didn't.

Isn't current thought that bouncing arises from the application of non-tangential force to the crank arms at the top or bottom of the pedal stroke, i.e. not pedalling circles?

bobscott

[WadePatton]

I must disagree with the notion above that bounce is not a result of energy being expended downwards after the pedal has begun moving rearwards. The reason it doesn't "bounce" us at low RPM is because we have much more time to manage that transition at lower cranks speeds atmo.

SO I tried the fore/aft shuffle today and found high rpm a BUNCH easier and way smoother, which is a great thing for a one-gear guy. Thanks.

Still learning to ride a bike...