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Spinning, part 3(3 posts)

Spinning, part 3Dog
Nov 2, 2001 9:34 AM
Someone got me looking at Bontrager's (mainly mountain biker) Rants in another thread. This one is actually sort of interesting:

Spinning

I've never had a chemistry class, or a piano lesson in my life, so I won't try to fake you out. But what I'm going to talk about this time will take a little chemistry and keyboards to understand. Luckily, I don't think I really need a background in these disciplines in this case (at least it's a lot easier to say this than to face the gruesome alternative of having to learn some). I think you'll get my point without knowing a thing about the Kreb's cycle or how to play a scale. We'll see.

Imagine that you are picking up something heavy over and over again, a human body in this case (admittedly heavier for some than for others). A pull up (chin up?) is a simple enough thing to do and we all do some for fun every now and then, right? You pull your body up until your chin reaches the bar, against gravity, by performing a series of muscular contractions, using a series of skeletal levers. You produce power. And when you've done too many, you stop; not because you want to, but because your body says it's time to stop. You have only one choice at that point.

The mechanical work you do is defined by the change in your height multiplied by the number of repetitions you perform. The power you produce, from a simple mechanical point of view, is the force you exert multiplied by the vertical velocity you achieve.

Try it a bit differently now. 10 quick reps and, in the middle of the lifting phase of the 11th, STOP. Now, hold this position, and as you do, try to convince yourself that you are no longer working. A mechanical engineer says you aren't. She also says that you aren't producing any power. Got a problem with that?

Now think about what your muscles are doing (as if you can avoid it - don't let up, you can hold it). They are not interested in the mechanical engineer's tripe; they don't need any of that to know what's going on. They say it's work, and that it's her problem if she disagrees. They're heating up fast and running out of means to continue. (Does knowing that help you hold the position? You can rest now, I'm done.)

This is a simple, if not painful, demonstration of a problem with approaching a problem with the wrong tools. There is another definition of energy and power besides the one used by the mechanical engineer. Chemical reactions occur in your body when you produce a muscular effort; whether you do mechanical work or not. Physiologists, taking a lesson from the legal profession, confuse lay people, sound pretentious, and try to make more money by calling it isometric exercise (one muscular length) and isotonic exercise (one muscular tension). These are, for our purposes, the same. Putting it in cycling terms, your body uses up power whether you are pushing on the pedals in a way that propels you along or not. Whether or not you ride a bike made of balsa wood or concrete, when you use your muscles, you produce power. If it doesn't make you go forward, it's a waste.

The roadies know this (well, maybe they don't actually "know" it, but they do things occasionally that would indicate to the impartial observer that, somewhere along the line, somebody connected to roadiedom figured it out). This is natural. They've been virtually completely out of things to talk about in terms of equipment development since they invented the pneumatic tire and derailleur, so they have to satisfy their hardware lusts with new paint jobs every other year and by improving their bodies to have more fun. There are roadie gearheads of course; they are modern humans (with some exceptions) after all. But these people are considered seriously deranged by advanced road scholars if they actually think they are getting down the pavement (tarmac) much faster than the next guy with their fancy widgets.

We should pity them in their disadvantaged state. Think how much less fun mountain biking would be if you couldn't go out and purchase some trick new bit now and then and feel real good about yourself for doing it. Instead these folks work on improving their bodies to go faster. The trainers, yes they have people who's job it is to figure out how their bodies can be forced to put out more power, make them do all sorts of weird things to this end. Some of it's jive of course, but some of it's the real deal. And the best of them actually submit to the trainer's evil suggestions and do the stuff. Then they go faster.

Take spinning for instance. That's a real sick one. You know, twiddling the pedals around, not really going anywhere but working your legs off doing it. Roadies spin a lot. They think it's a good thing to do because their trainer told them it'll make them go faster.

I recall being on a training ride one day (I'm a closet roadie I'll admit it, many of us were cause we didn't know any better back then), rolling down a gradual descent in Portola Valley with the "lunch time ride" boyz. This was a group of racers, exracers, and wannabes who went out at lunch time and tried to see how much they could intimidate each other, how much pain they could bear, and how much they could inflict on the rest of us. Nice bunch of road oriented guys.

Well here we were, together after the climb, in a fairly large bunch, going pretty fast down this long, straight, gradual hill. I'm in my 53 x 13 and I'm working to be here, not all out since there's a sprint coming soon, and, though I am never really contesting it, I'm happy if I can look up afterwards and see at least one rider behind me (the vanquished, you know, ego, competitive male sickness, testosterone poisoning, etc.). So I'm saving a little, but not nearly enough. That's why I design em now.

Anyway, I glance over and I see something that is devastating. Here's a guy riding a fixed gear bike, a track bike with a brake on the front only, spinning and grinning (part of the intimidation) along with the bunch. He made the climb on this thing, and now he's sitting in, twiddling along at 35mph. It turns out that it's set up at about 72". He's whirring and grinning along at well over 150 rpm. Sick.

Here's another twisted roadie story (confession cleanses the soul). Same situation, only this time it's the 6 o'clock ride boyz (6PM, I'm not that dedicated and few others are either) and we're going up a slight incline on Valencia Road. It's early in the ride so it's not too bad yet. I'm doing my usual presuffering suffering, and I glance over at the guy next to me. He's a notorious sprinter, too stocky to be much of a climber, and he's moving up to the front so he doesn't get sawed off on the climb that's coming up. He's spinning along, smiling again (it's part of the training - you don't just learn to spin - you learn to spin and grin) and he says to me, in a voice that indicated an overabundance of oxygen remained in his system, "Ridin' a bike's like playin' a piano". Then the philosopher twiddled up to the front - without shifting into a bigger gear. I never saw him again until after the ride. I won't go into the reasons why.

I didn't understand him at the time. I thought he was just messing with me, the other thing he was notorious for. He wasn't. He was right. Good bike riding depends on, to a large extent, touch. You have to learn how to pedal. The roadies know this.

Try this experiment some time, with a friend (who you trust with secrets), just to see how smooth you are. Start off down one of your favorite descents, a fairly fast one, but one that requires that you pedal hard in your biggest gear to do it right. Nothing too technical. Let your friend start off in front and they should do what they normally do in their big ring. You put your chain on your middle ring and keep it there during the entire descent. Can you keep up? The guys I was riding next to would be keeping pace, and grinning!

So what does all of this have to do with you and your 3d violet anodized wonder? Remember all of the convoluted bull I came up with about stiffness, how this or that could add up to a percent or so in power output? And before that I (tried to?) put lightweight parts in perspective. Both of those things are drops of spit on the top tube compared to pedaling efficiently. Whether your bike flexes or not, most of what you waste is in your legs, and it happens because you push down at the wrong time and in the wrong direction. The stakes here are much higher than a measly percent!

What the roadies figured out is that if you want to pedal efficiently, you have to learn to spin. Even the sprinters do it. The bottom line: If you want to be faster, tune on your motor. Either give it more usable horsepower or make it more efficient with the power it's got. You should make the rest of the equipment safe, competitively light, and durable, and maintain it all well, but the motor is what matters if you want to go fast.

http://www.bontrager.com/keith/rants.asp?id=9&ck=0&fl=1
re: Spinning, part 3zero1
Nov 2, 2001 10:09 AM
hey man...nice post...i am not very big. i only weigh around 130 lbs and i can not push those big gears so i have to spin...if i try to push the bigger gears i am dead in about 10 minutes...i guess it looks sort of funny to the bigger guys who push those gears and i am spinning my legs off....ride safe
re: Spinning, part 3badabill
Nov 2, 2001 10:22 AM
As a cofessed spinner it took me a few years to get this pounded into my head. To save the engine you must conserve energy. Bonty takes a long time to get there but what he says is true. Pedal efficiency is key to speed and endurance.