Meanwhile, the spinal side of the equation isn’t going to be stressed as much, because you still have your arms and the handlebars to help keep you from falling into your front wheel.
Exactly. Which brings us back to Sindre’s original point that started this thread.
If his premise is valid and at equivalent cadences and power levels, with PC riding there’s less force or emphasis on the downstroke. More bodyweight being supported by the hands and arms and/or a more upright riding position are symptoms of less force being applied during the downstoke. If more weight is being supported by the hands/arms and the rider is less aero/more upright, he’s also reduced the stress on his erector spinae when compared to riding with the same power and cadence with regular cranks. Simply view the upper body as a Class 2 or 3 lever with the saddle as the fulcrum and your torso providing the rigidity to the lever. The more you support the upper body with the force of the downstroke, the more the back and lumbar region is stressed.
The more you support the upper body with the force of the downstroke, the more the back and lumbar region is stressed.
Huh? Since the “support” from the downstroke is coming through the pelvis/saddle point of contact area it should have little or no effect on the stresses on the back. Pushing down more or less simply changes the forces on the other points of contact, the hands and the saddle, mostly the saddle as the rotational forces must balance also.You seem to be forgetting that pulling up also changes these forces. So even if pushing down more or less does change these stresses, pulling up more or less should change them in the opposite direction, making the overall effect essentially zero.
Sitting on a saddle in a normal competitive riding position, your body’s center of gravity is ahead of the saddle. Your body is supported by a combination of your legs during the downstroke and your hands/arms to keep your face from falling onto the stem.
Sindre’s assertion is that with PC’s he’s resting more on his hands and arms. We can therefore logically conclude that he’s applying less force on the downstroke. In order for him to lighten the load on his hands/arms through the force of the downstoke, he relys on the strength of his torso.
Sitting on a saddle in a normal competitive riding position, your body’s center of gravity is ahead of the saddle. Your body is supported by a combination of your legs during the downstroke and your hands/arms to keep your face from falling onto the stem.
Sindre’s assertion is that with PC’s he’s resting more on his hands and arms. We can therefore logically conclude that he’s applying less force on the downstroke. In order for him to lighten the load on his hands/arms through the force of the downstoke, he relys on the strength of his torso.
It is my thought that users deliberately “role forward” to put more weight on the arms, to take the weight off the saddle. This additional weight on the saddle doesn’t necessarily all come from pushing down less but also from pulling up more.
I guess right now it is simply a matter of speculation as to what is going on and someone someday will have to do some actual force measurements and analysis to determine what is really happening.
“If his premise is valid and at equivalent cadences and power levels, with PC riding there’s less force or emphasis on the downstroke.”
This is natural for the time that it takes for him to become more stabilized. It isn’t so much an issue of support as one of stability.
At equal cadence and power output, by definition force on the downstroke with PC’s is less than, or at theoretical best equal to, force on the downstroke with regular cranks.
One would also assume that the more ‘adapted’ the rider becomes, the more tangential force will be applied to the pedals on the upstroke and therefore at any given cadence/power output force on the downstroke will be de-emphasized. Thus the tendency towards heavier loads on the saddle and hands/arms as the originator of this thread describes. It’s simply a sum of forces. I don’t see where stability comes into play to any great extent here.
“One would also assume that the more ‘adapted’ the rider becomes, the more tangential force will be applied to the pedals on the upstroke and therefore at any given cadence/power output force on the downstroke will be de-emphasized.”
Agreed
“Thus the tendency towards heavier loads on the saddle and hands/arms as the originator of this thread describes.”
Heavier perhaps, but not as heavy as he’s experiencing now.
“It’s simply a sum of forces. I don’t see where stability comes into play to any great extent here.”
The inability to stabilize saps strength. Try standing on a wobble board, Bongo or an upside down Bosu and doing shoulder presses to see how this works. Once the stabilization is mastered, more strength can go to the pedals.
The inability to stabilize saps strength. Try standing on a wobble board, Bongo or an upside down Bosu and doing shoulder presses to see how this works. Once the stabilization is mastered, more strength can go to the pedals.
I’ll disagree.
Riding a bike is not like changing direction on a basketball court or swinging a baseball bat. On a bike, motion is constained and prescibed similar to a movement performed on a weight machine. On a bike, large muscle groups are what count. Synergizers and stabilizers are not heavily involved. Not that synergizers and stabilizers are unimportant… They’re just not that important when riding a bike at sub max intensities.
Sort of along these lines: when on PowerCranks, especially at first, I tended to rotate the top of my pelvis rearward, it helped the hip flexors not have to pull at quite such an acute angle. When I got on a non-PC bike, I found my pelvis would tilt back forward…and I could feel it more in my gluteal muscles. Now, I have a beam bike and my underside is much more comfortable than on a regular bike, so I find I can rotate my pelvis further forward…so now my gluteal muscles really get worked more.
Through it all, at every change, my mid-section seemed to get more tired than usual, too. I was guessing that my stabilizing or core muscles were being worked a little differently. Also, maybe I’m not using the same definition of core as others. By core, I mean muscles that aren’t attatched to limbs. I consider erectors to be a core muscle group…maybe that’s a faulty definition. But, when I do superman pose exercises, those erectors are firing, and I call it a core exercise.
Riding a bike certainly isn’t a core exercise like a balance board or ball, but, depending upon how much you use your arms to anchor, or how you cantilever your torso, and depending upon the definition of core, I think bike riding can require a significant amount of core stability. IOW, I can ride a bike easy using little core strength, but, I go much faster when using what I call my core…especially when climbing a hill or sprinting.
“Riding a bike is not like changing direction on a basketball court or swinging a baseball bat. On a bike, motion is constained and prescibed similar to a movement performed on a weight machine.”
Not with PCs
“On a bike, large muscle groups are what count. Synergizers and stabilizers are not heavily involved. Not that synergizers and stabilizers are unimportant…”
Stabilizers aren’t as important as the prime movers, but the thread started with the author noting that he was having difficulty stabilizing. ANY TIME youi are unstable, you will be weaker (in terms of getting the HP to the asphalt). It’s not a debatable issue. Try the simple experiment I gave you. Better yet, try it on your bike on the stationary trainer with PCs.
“They’re just not that important when riding a bike at sub max intensities.”
Not unless their not getting the job done. Then they become HUGE.
Your analysis is quite interesting to me. This instability “problem” is another explanation for the difference in difficulty some have over others and the drop in power most see for the first few weeks. In addition, it could explain the few returns we see for inability to adapt to them.
It would be an interesting research project but I am not sure how it could be done. How would one document this core instability on the bicycle, or would it have to be done off the bike.
What “tests” would you recommend for this evaluation?
Do you have experience with this and the PC’s? Did you notice an improvement? How long did it take?
How would one document this core instability on the bicycle, or would it have to be done off the bike.
If I read his post right, he’s not talking about core instability on a bike. He’s talking about core instability on a bike with PC’s. Big difference.
Allow me to quote his reply to my quote:
“Riding a bike is not like changing direction on a basketball court or swinging a baseball bat. On a bike, motion is constained and prescibed similar to a movement performed on a weight machine.”
Not with PCs
Might be important if you want to start marketing PC’s as a ‘core’ strengthening tool.
If I read his post right, he’s not talking about core instability on a bike. He’s talking about core instability on a bike with PC’s. Big difference.
Allow me to quote his reply to my quote: “Riding a bike is not like changing direction on a basketball court or swinging a baseball bat. On a bike, motion is constained and prescibed similar to a movement performed on a weight machine.”
Not with PCs
Might be important if you want to start marketing PC’s as a ‘core’ strengthening tool.
I think I understand the difference. On regular cranks people can (and do) use their recovery leg to stabilize things. This is not possible with PC’s. I do market them as core strengthening tools to rehab people. But, I had not thought of this PC bike core instability problem as he has andhow it might affect cyclists. If it is true, it should be measurable or does it not manifest itself in some way (easily) measurable. I guess the question is, is it measurable on the bike?