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#1
02-25-2009, 07:20 PM
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news flash: ti-designs "not a normal human"
and he doesn't pedal or walk like one either. so while the obama thread ponders the meaning of the communist revolution about to overthrow our capitalist system, I thought I would relieve some thread drift pressure off the triple chainring shifting performance thread to talk about how we pedal a bike. no need for ti to repeat his chair analogy and all the other posts about pedal drills and so forth, but I'm wondering what influence, say, saddle fore/aft and height have on fully engaging the quads and glutes, and while we're at it, why not cleat placement eventually too, since it seems to determine to a degree the transmission of power down the links (or does it?). set us straight.
I guess seated climbing technique could be a starting point too. if this is a dumb topic, let it die a slow death. 
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#2
02-25-2009, 10:31 PM
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Ok...I'll bite...
 I have played around with seating positions alot over the years and for me, I have found the balance for a fore/aft position. In getting there, I have tried progressively "longer" positions by putting the seat back a few millimeters at a time over the course of a couple of weeks. I have compensating by lowering a bit as it goes back. Conversely, I have gone the other direction, moving it gradually forward and raising the saddle just a bit with each move. This was mostly prompted by spending so many years track racing and having a more forward seating position. My road bike is setup is at 81cm seat height and 10.5cm of setback. My track bike is setup is at 83cm seat height and 8cm of setback. For the road, having a lesser saddle setback (less than 10cm) setup is not so great. I find while it does allow for quick acceleration and the ability to stay "on top" of a gear more easily, I have difficulty pushing bigger gears or when climbing. I find myself trying to scoot back, almost as if I were trying to get behind the gear rather than on top of it. By "on top", I mean winding up to 100 to 110 rpm and being able to sustain it. The deeper setback gives me the ability to "push" a bigger gear, meaning that I can turn a bigger gear slower, yet be able to sustain it. The road setup, with the 10.5cm of setback allows for a number of positions and the ability to recruit different muscles for different things. I slide back in the saddle and stay seated for all climbs but the steep short ones. I can generate more power at less cost by doing this. When I do a hard seated acceleration, there is a natural tendancy to slide forward on the saddle to "get on top" of the gear. My tools that I used to come to my "perfect postion" - allen wrench, power meter and HR monitor - not to mention some contol over variables in order to yield some reliable data (wind, rest, temperature, clothing). It's never perfect! These are just my simple explanations of many years of tinkering. YMMV.
__________________
-The older I get, the faster I was...
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#3
02-26-2009, 06:31 AM
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Quote:
You forgot one key tool - one which you'll never find in a fitter's toolbox. Time. No, not the french company!!! Time to change the position, adapt to the new position and then test. I have some guidelines on how I set up fore/aft position on the bike based on usage of quads vs. glutes in a static case, but there's no way for me to know what the real ratio of strengths of those muscles are, or how that changes with say a minute of hard effort. Yeh, an allen wrench (maybe two, if your seatpost and frame use different sizes - I've just doubled the cost of tooling!), time and a means of measuring change are better than the best fitter ever could be. You are also right about saddle height. The saddle to pedal distance goes around an arc. The center isn't exactly the BB, but it's easy to think of it that way. Move it back and you also move the saddle down. When talking about moving a saddle back and staying within your range of motion, there are two factors to look at. First, hip range of motion - moving the saddle back without changing where the bars or pedals are means increasing the angle at the hips. You don't have infinite range of motion at the hips, not even us "not normal" humans do. If as the pedal reaches the top of the pedal stroke you run out of range, your hip is going to lift and you'll start rocking in the saddle. The second problem is length. As you gain more setback, the greatest distance from saddle to pedal shifts forward from 6:00. In other words, if you have a mile of setback, you need to start looking at saddle to pedal distance from the top of the saddle to the pedal at 4:30. All too often I see people riding with what they think is the right saddle height, but as the pedal reaches that 135 degree point they go sharply toes down. giordana93, don't give up on the chair analogy so quickly, it's one that most people can relate to with ease. On the bike I try to get people to support their upper body weight with their glutes and it looks like they're trying to balance spinning plates on their nose. Once in a while I have to take someone off the bike, plunk them down in my seat (there's an added fitting charge if I have to stand during a fitting - I'm lazy). Everyone knows how to sit, for some reason sitting on a saddle with pedals under your feet is different... Anyway, give this a try - it's free! Sit on a chair, make sure your lower back is flat and as you shift forward the change happens at your hips. Place your feet on the floor in a natural position, then test out your full range of motion, all the way up to all the way down until you just start to roll off off the chair. If you're like most people you almost don't have to fire your quads in doing this. If you were to look at yourself from the side you would notice that as you got all the way down your center of gravity was right over your feet - this is how you learn how to stand up. It's not a simple position to work out. Where your feet wind up on the floor depends on how long your femurs are, how long your torso is, your lower back range of motion and where your upper body's center of gravity is. It's a lot like the complexity of riding a bike - you can teach a 4 year old in minutes, but build a machine to do the same thing and it gets complicated. OK, now move your feet back a little and try the same thing, you'll start to feel your quads fire. As your center of gravity gets forward of your feet that's the only way your body can hold your position. Move your feet in the other direction and your hamstrings start to work. So how does this translate to the bike? When I work with a rider on fit, my goal is to give them enough setback to allow them to use the glutes to both support their weight on the pedals and disengage the quads from the action. This is only one of a few parameters, keeping them within their range of motion still counts... In very simple terms, setback allows the rider to gain angle at the hips, which use the glutes. A more forward position allows the quads to kick over the top better - like I said, simple terms. The different muscle groups have different strengths and abilities. Glutes are strong, able to withstand huge amounts of torque and in the position to leverage the upper body weight using gravity. If the glute isolation drill is done right you should feel like you're falling forward onto the pedal. Gravity is a constant. If you're expecting acceleration from gravity you had better move to another planet. Quads don't use gravity and can contract faster. If you're looking for acceleration of the pedals, it's going to be the quads that do that work. In my pedal stroke class I go over form for intervals, which is all about using all three muscle groups to their greatest advantage. The interval is 30 second, but there is a sharp increase in gear size at the start and it's all about power. So, as soon as the interval starts the pedals slow from the gear change, and the rider is looking for a muscle group that can handle that kind of torque. The normal argument I always get is "why not use all of them". Try powering your big chainring with your hamstrings, small muscle group vs. high muscle tension, the hamstrings lose. The first four pedal strokes are all glutes, all body weight being thrown at the pedals. That gets the bike up to speed, but then gravity isn't going to make it go any faster. Step two, without changing the body position and how the glutes are working, add the quads kicking over the top. You should hear a change in the pedal stroke, and the speed should increase. Note: my pedal stroke class is 6 weeks of learning how to use each muscle group to the point where it's second nature before they get added together. The pedal stroke is a lot like learning how to juggle, there are steps you can't skip or it just doesn't work. Getting back to the interval, somewhere past the midway point you start shifting the emphasis from the quads to the hamstrings to hold speed for the whole interval. Withing that example of an interval, fore/aft position could change just based on gearing selection. On my road bike I use the 55/11 or 12 for intervals, the glutes have to work hard from start to finish and the RPMs never get super high (but the noise is impressive). I like climbing and I'm know to throw in a few stupid attacks now and then. On my track bike I'm turning a 48x14 in interval training, it's all about driving out the RPMs.
__________________
If the pedals are turning it's all good.
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#4
02-26-2009, 06:40 AM
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i can attest to the fact that ed does indeed ride a dinner plate as a big chain ring.
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#5
02-26-2009, 08:08 AM
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ed, I wasn't giving up on the analogy and even less questioning it; rather, I didn't want you to be obliged to write it out once more, because most of us who have been around long enough have read it and maybe partially digested it. it takes time to write your thoughtful posts, so I was skipping the first grade level to get more into the discussion.
2. my biggest fit debate lately has really been on saddle height, and to a lesser degree, fore aft. for historical/morphological reasons, I've always been on a small frame for my height (can we abbreviate everything as Ht for rider height, Hs for seat height, and SB for seat set back? are there other conventions?)..... because I'm 5'9" but have pretty short legs at 79.5cm, so the "by the book" fit of the 80s put me on a 52. now what is interesting is that with a fairly low saddle height but pushing back towards the rear of the saddle, I get more or less the same extension as a higher more forward saddle, and this is how I always rode. NEVER had any back issues, and always able to get pretty low because I "unhitched" my back and pelvis by rolling everything way forward. the only problem was that, with most of my weight to the rear, I wasn't really in the "on top of the gear" position, and frankly since I quit racing ages ago, it didn't really matter I guess, but now that I've finally decided to replace the giordana, or at least give it a backup, I've been struggling with figuring out the equation again. in short, if I ride with a higher, more forward saddle, I can never really do that "unhitch" move of really changing from the seated climb, upright (well, 45degree) position to the rolled over, straight and very flat back position. it just doesn't happen in part because I don't have the hamstring flexibility, and in part because that roll forward effectively raises the seat, so with the seat already at a maximum tolerable Hs,it's just too high for the roll. short story, I end up looking more like Lance than Lemond, if you know what I mean. which is not necessarily bad, as I can still recruit most of the same muscles, and there is certainly a different power phase from getting the full leg extension while having my weight more forward (it's not a position for taking the "bike walk" and pretty much demands one to be working or to suffer a little more weight on the hands). but it's also a lot harder on the back, at least when I'm not fit, and because of a dumb luck accident last year, I've never really been able to put the miles into that position. I do know that the lower and rolled forward position feels like "home" and even with low mileage I can go and knock out a quick ride and not have any issues with back or knees but I didn't want this to be just about me, so to sum up, how have others negotiated this ability to roll the hips forward which requires an itsy bit lower seat and perhaps further back (still haven't figured out if I can duplicate this with a higher bar but a longer stem), how does this relate to your own kops minus X cm position.. have you taken to a higher bar position to accommodate a higher seat. whatever.
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#6
02-26-2009, 08:36 AM
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Interesting take on dynamic saddle height and fore/aft adjustment. Back when I was racing I used the Concor saddle, which was larger than the new version with a lot of raised lip at the back. I would glue a wide rubber band to the last 1/2" of the saddle, so when I shifted back in the saddle for a bit more height and setback it would stop me from going too far.
I have a feeling that not being able to get "on top of the gear", or not using the quads well going over the top has more to do with range of motion than saddle height. I've worked with many riders who rotate way forward from the hips and basicly fold themselves in half in the name of aerodynamics. The best way to show the cost of that in terms of power in the pedal stroke is to have them pedal slowly with on foot clipped in. Aside from the fact that their hip has to come up with every pedal stroke (a sign that you're outside of your range of motion), I stop the pedal at 11:00, put one finger against their shoe and tell them to pedal the bike. They simply can't. The hip flexor can't lift the pedal any more so as the quad tries to extend the lower let it's trying to move the pedal into the pedal circle, not around it. That's a battle you can't win, the cranks are stronger than the rider...
__________________
If the pedals are turning it's all good.
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#7
02-26-2009, 08:45 AM
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Quote:
Now to put all those new factors into practice, here's where I ended up: My saddle height was lowered slightly. My saddle fore/aft was pushed back slightly. My bar height was raised slightly. I was able to do most of this because of the fit and because of the geometry of my CSI compared to my old C'dale Criterium. When I went to a longer crank AND moved back, I began to run out of room for my knees to come over the top of the stroke (short torso = less room to bend). In a way, this was a good thing, because it almost forced me to consistently keep my heel level or even dropped slightly as I come over the top of the stroke (to keep my knee out of my chest). All of these small changes really helped power and smoothness. With a farther back position, I can recruit the hamstrings better to help pull the pedal through the bottom of the stroke, use the glutes better to push the pedal down and use the quads better to push the pedal over the top. It seemed to help shrink the 'dead' spot between 9 and 12 o'clock (viewed from the drive side). This all goes to point out how having a good fitter with a range of bicycle geometries upon which to draw is so important. We really have to fit the bike to our bodies, and not the other way around. As an aside, I also have a compression fracture on one side of my L3 vertebra. This causes my right leg to be 'short'. I shim the right cleat about 4 mm to compensate. It only took me 7 years of riding/racing to get to this position.  Mike in AR 
__________________
2013 Serotta Fondo Ti w/Enve fork
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#8
02-26-2009, 08:50 AM
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well it's not so much about not being able to be on top of the gear, I use that as a kind of common expression, it's much more the debate between being able to truly effect a flat straight back all the way from the sit bones, vs sit bones being at one angle with a bend in the back initiated as close as possible to the saddle but still there. it's really that lemond vs lance look (I know, LA has the congenital back thing going, but it's just easier to see on him what I'm talking about)
by the way, I definitely prefer, at least in the past, a flat saddle with a lip or raised tail at the back, precisely because it cradles me in that positon. re: your hip flexor point there, I don't seem to have that issue, but I'm wondering if that too might have something to do with the saddle fore aft. i.e. if you are closer to kops, definitely harder to do what you're saying, but a little further back, that 11 (TDC almost, right?) is easier to get over because your'e still pushing from behind. might that be why lots of people like kops - a cm or two? (besides the easier ability to cantilever one's weight for the "balance test" (the ability to take your hands off the bars without falling on your face))
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#9
02-26-2009, 08:59 AM
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Quote:
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Linear Mode
