Percentage vs. linear weight...

[powerplant42]

O.K. This may sound like a dumb question, but we were having fun with it in another thread. Which matters and why: Percentage of weight on a pole, or linear weight on a pole?

http://www.polevaultpower.com/forum/viewtopic.php?t=12982&postdays=0&postorder=asc&start=12

[Lax PV]

I would agrue that percentage of weight on a pole is going to make a bigger improvement. Very few things in athletics are linear. Just because you can squat 100 pounds 10 times, doesn't mean you can squat 1000 pounds once (more likely if 10 at 100 was your maximum, one would top out around 135ish).

That being said, if you are say 150 pounds, on a 160, you are at about 93.7%, but now if you gain 5 pounds, and can get on a 170, you are at about 91.1%. If you were to gain 10 pounds, be weighing 160, and on a 170, your percentage is now 94.1%, so the linear model actually made your weight closer to the weight rating of the pole.

I think it goes without saying, the bigger the gap... the better chance of jumping high

[powerplant42]

Now one must think... Is a pole like a scale or a spring? I'd say spring. If you put 10 pounds hanging from a spring, it will uncoil to ten pounds. If you put on 15, it will only uncoil 5 more pounds. A spring's resistance is linear, yet a counterweight scale resists parabolicaly. (Doesn't it?) But this is the argument! I wish more people would put in their say!

[Lax PV]

Now one must think... Is a pole like a scale or a spring? I'd say spring. If you put 10 pounds hanging from a spring, it will uncoil to ten pounds. If you put on 15, it will only uncoil 5 more pounds. A spring's resistance is linear, yet a counterweight scale resists parabolicaly. (Doesn't it?) But this is the argument! I wish more people would put in their say!

great comback. a scale is more parabolic in that it "sways back and forth" till it settles at the correct measurement. but a scale uses springs..?

my thought is since (to the best of my knowledge) the flex system is linear (i.e. for a 15' stick, 5 pounds accumulates every .8 to 1.0), shouldnt the pole be linear too? And given that the pole weight rating is linear, 5 pounds at a high weight, vs. 5 pounds at a low weight is inconsequential... it's still 5 pounds. Thus, making it less of a difference, percentage wise, when the numbers increase...

But.. on the otherhand... a 6 inch PR is much easier to attain at a novice height, than it is when you are beginning to jump something more advanced...

thoughts???

[rainbowgirl28]

my thought is since (to the best of my knowledge) the flex system is linear (i.e. for a 15' stick, 5 pounds accumulates every .8 to 1.0), shouldnt the pole be linear too? And given that the pole weight rating is linear, 5 pounds at a high weight, vs. 5 pounds at a low weight is inconsequential... it's still 5 pounds. Thus, making it less of a difference, percentage wise, when the numbers increase...

It's not linear. Someone else much smarter than me can explain it a lot better, but at the really soft flexes, 1.0 might be like a 5 pound jump while in the really stiff poles it might be like .4. That is why the elites have poles that are so close in flex numbers.

[powerplant42]

Cool! I learned something today! I'm still trying to figure out why this is though... Does anyone know of an article or know a physicist who could explain this? It's pretty annoying...

[Lax PV]

my thought is since (to the best of my knowledge) the flex system is linear (i.e. for a 15' stick, 5 pounds accumulates every .8 to 1.0), shouldnt the pole be linear too? And given that the pole weight rating is linear, 5 pounds at a high weight, vs. 5 pounds at a low weight is inconsequential... it's still 5 pounds. Thus, making it less of a difference, percentage wise, when the numbers increase...

It's not linear. Someone else much smarter than me can explain it a lot better, but at the really soft flexes, 1.0 might be like a 5 pound jump while in the really stiff poles it might be like .4. That is why the elites have poles that are so close in flex numbers.

that actually makes a lot of sense... thanks for the heads up.

[Barto]

Cool! I learned something today! I'm still trying to figure out why this is though... Does anyone know of an article or know a physicist who could explain this? It's pretty annoying...

I'm not a physicist but I might be able to explain. There is a theoretical point at which poles will not flex at all. As you approach this point, the relative stiffness of the pole will increase more and more with equal differences in flex numbers. Thus the more stiff the pole the less difference in flex number to equal the same amount of stiffness.

[powerplant42]

What do you mean when you say that there's a point where it won't flex?

[Barto]

It is theoretically possible to make a pole that will not bend no matter what force is applied to it.

[Lax PV]

its partially due to the idea that force is a parabolic curve... as force is continually added, the velocity continues to rise, therefore the position of the object will exponetially speed up. Likewise the opposite is true. As the pole forces back, it resists the movement, eventually getting to a point where the bending of the pole is negligable.

I'll spare you the hardcore physics of it... but barto has it down...

[master]

its partially due to the idea that force is a parabolic curve... as force is continually added, the velocity continues to rise, therefore the position of the object will exponetially speed up.

huh?????

- master