Maximizing the Long Jump of Bryan Clay

The long jump is one of the most technically challenging events in the decathlon, a track and field competition consisting of 10 events held over two days. In order to maximize his performance, 2008 Olympic gold medalist Bryan Clay teamed up with engineers from BMW to improve measurement of the horizontal and vertical velocities of his long jumps. "Science of the Summer Olympics" is a 10-part video series produced in partnership with the National Science Foundation.

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LIAM McHUGH, reporting: For the past four years, Bryan Clay has held the title 'World's Greatest Athlete.' It's an award bestowed upon the Olympic gold medalist in the decathlon, a competition consisting of 10 track and field events held over two days.

BRYAN CLAY (Olympic Gold Medalist): On the first day, we do the 100 meters, the long jump, the shot put, the high jump, the 400. And the second day, we do the one-ten hurdles, the discus, the pole vault, the javelin, and the 1500.

McHUGH: While Clay ultimately failed to qualify for the 2012 Games in London, he used advanced technology to prepare for the long jump, one of the decathlon's most technically challenging events because it requires the athlete to sprint down the runway and launch himself at the exact moment that he reaches the take-off board.

CLAY: That's where the difficultly lies is learning how to come in with somewhat of a rhythmic run-up, and then hit the board with as much accuracy as possible. And then, of course, catapult yourself and jump as far as you can into the sand.

MELVIN RAMEY (USA Track & Field): When a person jumps to try to go far, they are becoming a projectile. So the human body is functioning as a projectile.

McHUGH: The mechanics of projectile motion are critical to Clay's performance in the long jump. Clay's velocity has two components - horizontal velocity, his sprinting speed, represented by 'X'; and vertical velocity, his lift-off speed, represented by 'Y.' From the time he leaves the ground, gravity pulls Clay down, changing his vertical velocity but not his horizontal velocity, causing him to follow a parabolic path until he lands in the sand pit. Melvin Ramey, an engineer who has been supported by the National Science Foundation and a biomechanist for USA Track & Field, says that by measuring Clay's horizontal and vertical velocities, it's possible to find a crucial element of the jump, the take-off angle, which will ultimately determine the length of the jump.

RAMEY: In general, world class jumps are takeoff angle somewhere between 18 and 22 degrees.

McHUGH: In order to accurately measure it, Ramey and Clay are turning to an unlikely place for help. As part of a sponsorship package with the U.S. Olympic Committee, BMW is lending its engineering expertise by adapting a cutting-edge stereoscopic camera system to measure Clay's jump.

PHIL CHEETHAM (United States Olympics Committee): The BMW velocity system is using what we call a 3D camera or a stereoscopic camera. It actually has two lenses and so it can triangulate everything that it sees in the field of view. They've made it recognize a template and that template happens to be a white baseball hat.

McHUGH: As Clay sprints down the runway, the stereoscopic camera tracks the white cap on Clay's head, the most stable part of the body in motion, and takes pictures 60 times per second to calculate his horizontal and vertical velocities at take-off.

CLAY: What's the velocity here and the velocity here? The x velocity and the Y velocity?

CRIS PAVLOFF (BMW Technology Office): So this is Y. That's going to be like how much you're going up and X is going to be how much you're going forward and then the angle is going to be between your velocity this way and your velocity this way.

CLAY: Oh ok got you.

PAVLOFF: We're able to find the angle between these two vectors.

McHUGH: Some cars are already loaded with cameras to provide drivers with feedback about what's around their car. But at the BMW Technology Office in Mountain View, California, Cris Pavloff is developing a future safety system that uses the stereoscopic cameras - similar to those used on the track with Bryan Clay - with specific computer software that calculates an object's distance from the car - such as a pedestrian crossing the street.

PAVLOFF: What we have here is a car that has depth perception. Current systems say, yes, there's a pedestrian. This can say, yes, there's a pedestrian and it's twenty-two and a half meters in front of the car.

McHUGH: While this stereo camera system is still in development for automobiles, the system at the Olympic Training Center has already provided valuable feedback to Clay and his coach.

CLAY: With this technology, we actually will know how fast we're running, how much velocity we're maintaining off the board, and then we can actually do some calculations to see how far of a jump that should have been and how far of a jump it actually was. Yeah, it could be better.

RAMEY: Still out.

CLAY: Still out a little bit.

McHUGH: Ramey says the BMW technology is useful because it provides real time feedback.

RAMEY: This equipment gives it to us instantaneously. In other words, actually while the athlete is in the air, we have already captured those velocities. So the advantage that we have now is that the coach can come and look at the performance immediately.

CLAY: Now you can find the optimal take-off angle.

McHUGH: Vital information for decathletes like Clay who train and push themselves on the track six or seven hours a day.

CLAY: The more efficient we can be, the better off it's going to be for us, because we have to save energy, we save time, we have more time to recover, less pounding on our body and our joints, which leads less injuries. So all of that stuff can make a very big difference.

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Track & Field