Sunday, Jun. 25, 2006

Sphere of Influence

By MATT SMITH

For some, it has been the World Cup's most unwelcome guest: the ball, the Adidas Teamgeist. Goalkeepers such as England's Paul Robinson, Germany's Jens Lehmann and the U.S.'s Kasey Keller have all criticized it, arguing that it's "goalkeeper unfriendly." Adidas, on the other hand, fiercely defends its product, claiming that the complaints are as hollow as the ball itself. Who's right?

The problem is not one of size or weight; Teamgeist is the same size as the last two World Cup balls and maybe a few grams heavier. But its paneling is new. The 1970 World Cup introduced the iconic football design: 32 black and white pentagonal and hexagonal panels. Teamgeist, by contrast, has 14 panels premolded in the shape of a sphere, all of them bonded instead of stitched. That produces what Adidas calls its roundest ball and smoothest surface. Adidas production manager Rene Skytte says the Teamgeist has "a much bigger sweet spot," but its critics say that its unique paneling makes the ball move unpredictably.

Lehmann claims the ball "flutters"; Keller says it "wobbles." They may be onto something. Similar to baseball's knuckleball pitch, a football struck without spin will move from side to side in the air. But keepers shouldn't worry. In a study conducted at Sheffield University in May, Matt Carré found that the Teamgeist's paneling does result in its "fluctuating more often" while in the air. "But," he says, "we found that it ended up in the same place more often." That's because the increased number of fluctuations — what looks like fluttering or wobbling — allows the ball to "correct" itself before reaching its target, which results in a more consistent shot. Try telling that to the goalies.

David James, another Sheffield engineer, asks the key question: "How much is it the ball and how much is it the players?" Just as Brazilians are credited with first getting a football to bend in the 1950s, today's generation of strikers may have figured out a new way of tormenting goalkeepers — but this time with shots that have no spin at all.