Along with vuvuzelas, controversial goals and Diego Maradona's overzealous touchline demeanor, the problematic Adidas Jabulani has become a leitmotif of South Africa 2010. The ball was designed by boffins at Loughborough University, England, and every effort was made to give it superior aerodynamics: the panels are stitched internally to create a near-perfect sphere, and Adidas' "Grip'n'Groove" technology is intended to aid consistent flight.
A set of boffins in France, however, have resisted the urge to go on strike long enough to establish that the ball has been giving inconsistent results in the tournament because it is a little too "perfect". AFP reports:
Part of the problem may be that "the stitches of the Jabulani are internal, so the ball resembles a perfect sphere," said Eric Berton, deputy director of the Institute of the Science of Movement in Marseille, France.
"Because of the shape, the time of contact with the foot is reduced. As a consequence, it practically doesn't spin. The ball travels a little less far, and will have a floating and unpredictable trajectory, whether for a striker or a goalkeeper."
I'd question whether the ball travels "a little less far", as keepers have been pinging the Jabulani from box to box with ease at this tournament, but it's unpredictability is certainly not up for debate. Iker Casillas has called it "rotten", Luis Fabiano thinks it's "supernatural", and Diego Maradona believes its uncertain flight has resulted in less long passes.
Wind tunnel tests have been conducted by academics in Japan, Australia and California, and each suggested the ball is a bit rubbish thanks to its tendency to slow down mid-flight. The original wind tunnel tests have also been criticized as they were performed on a stationary ball, and hence they did not simulate how the ball travels during a game.
FIFA, who seem to be in an uncharacteristically apologetic mood this week, has also acknowledged the super-spherical ball has its faults. A very sensitive-sounding Secretary General Jerome Valcke said this weekend:
"We're not deaf. FIFA is not unreceptive about what has been said about the ball."
While the Jabulani has been universally panned, several players have spoken positively about it: Kaka approved of the contact it offers, Petr Cech liked the way it felt, and before he used it to hit the crossbar twice with one shot, Frank Lampard said it was "true to hit". And you'll never guess which German sportswear company those players are sponsored by...