How the Fosbury flop made other jumping techniques obsolete

HostIt's funny how we just assume the best way to do something has always been obvious. For a long time, if you wanted to jump over a high bar, you did it face down. Then a guy named Dick Fosbury tried it backward. People thought he was a joke. Coaches told him he would break his neck, and newspapers even drew cartoons of him looking like a fish flopping out of a pond. I want to look at why that flop actually changed everything. Was the old way really that much worse?

GuestIt was, but not because the athletes were weak. Before the late sixties, almost everyone used what they called the straddle. You would run up and basically roll over the bar with your belly facing the ground. It looks like a very athletic crawl through the air. But there's a huge problem with that. When you jump like that, your center of mass, which is basically the average spot where all your body weight is bunched up, has to clear the bar by at least a few inches. Since your whole body is draped over the bar at once, you have to lift every single pound of yourself higher than the obstacle.

HostSo it was just a contest of who had the most raw power in their legs?

GuestPretty much. You could only jump as high as you could physically lift your entire weight. There was a hard ceiling on how high a human could go because you were fighting a very simple rule of physics. You had to shove your whole mass up and over. There was no way to be sneaky about it or use better mechanics to get an edge. You just had to be more explosive than the next person. But then Fosbury changed how he even got to the bar. He started running in a shape like the letter J.

HostI have seen that. They don't run straight at it, they sort of loop in from the side. Does that really help you jump higher?

GuestIt does, and here is why. When you run on a curve like that, it creates something called centrifugal force. It's that same feeling you get when a car turns fast and you feel like you're being pushed toward the door. Fosbury used that force to lean away from the bar as he ran. At the very last millisecond, he would snap his body back to being vertical. That lean let him lower his center of gravity before he even left the ground. It gave him a much longer runway to build up speed and then explode upward. He was turning forward speed into a kind of upward twist that the old straight line approach just couldn't do.

HostThat sounds like he was just building up a lot more speed. But the actual jump, the part where he arches his back over the bar, that's the part that looks like a cheat code.

GuestThat's exactly what it is. It's a cheat code for gravity. When Fosbury flopped over backward, he arched his back into a deep curve. As he went over, his head and shoulders would drop down on the far side while his legs were still on the near side. Because of that extreme arch, something wild happens. The athlete’s center of mass actually passes several inches underneath the bar, even while their physical body goes over it. You're basically moving your body over the bar in pieces. First the head, then the hips, then the feet. You never have to lift your whole weight over the bar all at once.

HostWait, so the math says he's not even jumping high enough to clear the bar, but he still makes it?

GuestYes. He's using geometry to get around the physical work of lifting his weight. He could clear bars that were mathematically impossible for anyone using the old belly down style. The straddle jump was like trying to lift a heavy box over a fence. The flop is like sliding a long rope over that same fence. The rope is never all on top of the fence at the same time, so it's much easier to move. It made every other way of jumping obsolete overnight because no amount of leg strength could beat that kind of efficiency.

HostIt seems so obvious now, but if it was that much better, why didn't someone figure it out decades earlier?

GuestWell, the physics were always there, but the technology was not. For a long time, high jumpers landed in pits filled with piles of sand or sawdust. If you try to land on your neck or your upper shoulders in a pile of sand after falling seven feet, you're going to get hurt. You might actually break your back. It was only in the sixties that tracks started using deep, soft foam rubber mats. Those big cushions acted as a safety net. Without that foam, Fosbury never would've had the chance to experiment with landing on his back. The sport was stuck because the landing was too dangerous to try anything else.

HostSo we needed the right gear before we could find the right physics.

GuestThe foam let him fail safely until he found a way to jump that shouldn't have been possible. He proved that you don't have to lift your whole weight over a hurdle if you're smart enough to move around it.

HostIt turns out that flopping like a fish was actually the most scientific way to fly. Those coaches who were worried about his neck were just looking at a man who had found a better way to fall.