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  • In the early 1960s,

  • Dick Fosbury tried his hand at almost every sport,

  • but never excelled at anything,

  • until, at the age of 16, he turned to the high jump.

  • But when he couldn't compete against

  • the strong athletes at his college

  • using the standard high jump techniques of the time,

  • Fosbury tried to jump a different way: backwards.

  • Instead of jumping with his face towards the bar,

  • bringing each leg over in the

  • traditional straddle method,

  • he jumped with his back towards the bar.

  • Fosbury improved his record by over half a foot,

  • and left his coaches amazed

  • by this strange new style of high jumping.

  • During the next few years,

  • Fosbury perfected his high jump style,

  • won the U.S. National trials,

  • and assured his place in the 1968 Olympics in Mexico.

  • In the Olympic Games, Fosbury amazed the world

  • with his new technique, winning a gold metal

  • with an Olympic record leap of 2.24 meters.

  • By the next Olympic Games,

  • almost all of the competing of high jumpers

  • had adopted what came to be known as

  • the Fosbury Flop.

  • What's the secret behind the technique?

  • It lies in a physics concept

  • called the center of mass.

  • For every object,

  • we can locate the average position of all of its mass

  • by taking into account how the mass

  • is spread around the object.

  • For instance, the center of mass

  • of a flat, rectangular object of uniform density

  • will be in the intersection of both diagonals,

  • in equal distance from each corner.

  • We can find the center of mass for other objects

  • by similar calculations,

  • or by finding the object's balancing point,

  • which lies right underneath its center of mass.

  • Try balancing a broom by holding it

  • and slowly bringing your hands together until they meet.

  • This balancing point lies right underneath

  • the broom's center of mass.

  • We humans also have a center of mass.

  • When most people stand up,

  • their center of mass is around the belly,

  • but what happens to your center of mass

  • when you lift your hands in the air?

  • Your center of mass moves upwards.

  • It moves all the time as you move through the day,

  • based on how your body is positioned.

  • It can even move outside of your body.

  • When you bend forward, your center of mass

  • is located below your bent belly

  • in a place where there is no mass at all.

  • Weird to think about, but that's the average position

  • of all your mass.

  • Many objects' center of mass

  • are outside their bodies.

  • Think of doughnuts or boomerangs.

  • Now look at the Fosbury Flop, and follow the position

  • of the center of mass of the jumper.

  • The jumper runs very fast,

  • so he can divert his horizontal velocity

  • to vertical velocity, and jumps.

  • Wait for it...there.

  • Look at the jumper's center of mass

  • as his body bends backward.

  • It's below the bar.

  • That is the secret behind the jump.

  • With the old, pre-Fosbury techniques,

  • the jumper had to apply enough force

  • to lift his center of mass above the bar

  • by a few inches in order to clear it.

  • The Fosbury Flopper doesn't have to do that.

  • The genius of the Fosbury Flop is that the jumper

  • can apply the same amount of force,

  • but raise his body much higher than before.

  • That means he can raise the bar so high

  • that even when his center of mass

  • can't go any higher, his arching body can.

  • Fosbury's technique brought

  • the high jump to new heights

  • by splitting the jumper's body

  • away from his center of mass,

  • giving it that much more room

  • to clear higher and higher bars.

  • So the Fosbury Flop may be sports history's

  • only great leap forward,

  • that is also a great leap backward.

In the early 1960s,

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TED-ED】世界記録を打ち砕くアスリートは物理学を使っている - Asaf Bar-Yosef (【TED-Ed】An athlete uses physics to shatter world records - Asaf Bar-Yosef)

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    阿多賓 に公開 2021 年 01 月 14 日
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