Sunday, November 28, 2010

"We do sprint training."

A common question I'm asked by my curious peers is: "How do you train for pole vault?" I used to give them a detailed summary about how I drive out to train with this other coach in that other far city once or twice a week, and how we do "bar work" and do drills.

However, after pole vaulting for a few years now, I've boiled down my answer to: "We do sprint training."

Why is sprint training so important in pole vault? Sure, it takes no-nonsense abdominals to perform those top-of-vault contortions. And it takes gnarly arm strength to prevent the pole (your "friend") from performing a blunt and glorified back-stabbing. Despite the blatant importance of upper-body strength, pole vaulters spend the majority of time training to run faster.

There is wisdom in this.

Observe this complex diagram.
The pole vaulter of mass m runs with velocity v to clear height h.

And also, recall the equations for kinetic energy and potential energy.

Kinetic Energy = ½mv2
Potential Energy = mgh

In a simple world, the vaulter's kinetic energy equals his potential energy.

m = mass of vaulter
v = velocity of vaulter when he plants the pole
g = acceleration due to gravity (9.81 m/s2)
h = height of crossbar

½mv2 = mgh
v2 = 2gh
v = √2gh
v = √19.62h

Thus, a pole vaulter "can vault only as high as he can run."

How fast was Bubka running into his world record vault?

The Bubka-beast.
v = ?
h = 6.14 m (20.2 ft)

v = √19.62h
v = √19.62(6.14)
v = 11.0 m/s (24.6 mph)

That's pretty amazing-- Can people even run that fast?

Usain Bolt holds the current world record for the 100 meter dash. His top speed is 12.2 m/s (27.3 mph).

So yes, people can run pretty fast, and Bubka is, in fact, as fast as a world class sprinter (keep in mind that he has to sprint while holding a fifteen-foot pole).

1 comment:

  1. I like the way you really simplified the physics - a pole vaulter can only jump as high as he can run (or something like that). It is true! It's an energy conversion issue. We will study more about it in a few weeks.

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