However, since this force is applied to the feet, away from the center of mass (to > 0), a torque will be produced. In this case, the torque would cause a forward angular acceleration, which would tend to deposit the diver face down in the sand.
So athletes use a Some different techniques To counteract this rotation, the first thing is lean back In the jump, this moves the center of mass closer to the point of contact of the foot, thus reducing torque. But it also makes you slower. Another is the Hanging techniquewhere the jumper extends his arms and legs like a giant sail in the air. As we have seen, this increases his moment of inertia, perhaps at the cost of a little additional wind resistance.
The method used by most Olympic athletes is the hook kick (Shown here by Carl Lewis(Who won four gold medals in the event). It looks as if the jumper is running in the air, moving his arms and legs like windmills as he flies. What this does is transfer the rotation of the body into a rotation of the arms and legs. (Technically, it’s a form of conservation of angular momentum.) People often think that this running motion makes the jumper go farther, but that’s not the case: with traditional techniques, the distance is pretty much set once you take off, just like in our ball model above. It’s all to fight the rotation so that you can land well.
The somersault
Tuariki Delamere’s approach was radically different. Instead of trying to fight the rotation, he said, why not go with the flow and wear That rotation? If you lean forward As the back foot pushes off, you can produce even more torque and perhaps more jumping force as well. After that, you could simply continue the rotation until you land on your feet… hopefully.
But wait! There is another benefit, too. If the jumper bends his knees towards his chest, this will increase his angular velocity (like the ice skater above). This would also give him a smaller cross section in flight, which would reduce air resistance. The effect would be small, but remember: small differences can win a gold medal.
The somersault long jump has another interesting benefit: as the athlete spins in the air, the tucked position brings the feet forward quickly to make contact with the ground. In front of the jumper. If you do it right, you will roll forward so as not to fall backwards onto the seat or your hands.
Delamere’s technique could have added significant distance to the long jump. Many experts believe he could have broken the 30-foot mark (the world record is 29 feet 4 inches). But he was never given the chance, because the sporting authorities said it was too dangerous. Evidently, they had never seen gymnastics or ski jumping.
My opinion? Athletics veterans cared more about their traditions and had no time for ostentation and creativity, especially if it meant breaking established records. Maybe that will change. Who knows? After all, breakdancing is now an Olympic discipline!
