Another reason why the granny shot helps a free thrower win cheers rather than jeers: It gives a backward spin to the ball. If a ball with backspin happens to hit the metal rim of the basket, the friction of contact suddenly reduces its forward velocity. “It’s like a drop shot in tennis. The ball bounces, but it doesn’t have a forward motion on it,” Brancazio says. This effect tends to freeze the ball at the rim and greatly increases the chance that it will tip into the basket rather than ricochet off.
The underhand throw can also minimize the drift of the ball. “A little sideward nudge at the start of the throw will translate into a big movement toward the end,” says Tom Steiger, a researcher who taught basketball physics at the University of Washington in Seattle. The trick to keeping the ball moving along a single plane toward the basket lies in “minimizing the sideways motion,” he says. “In other words, you have to keep your elbows tucked in.” If they are sticking out, that can easily add an unwanted nudge to the ball, which results in a missed shot. The underhand throw provides better stability than the overhand “because you’re holding the ball with both hands,” Steiger says. This helps players balance the subtle motor muscles in the hands and keeps them more relaxed. The movement of the underhand throw is a simple, easy-to-control upward pendulum motion. By contrast, the more conventional overhand free throw shot involves separate movements of the wrist, elbow, and shoulder that can add errors, Steiger says. “If the ball ends up rolling off one side of your hand even a little bit, you’ll miss.”
Despite the logic of a granny approach to foul shooting, no NBA player has used it since Barry retired in 1980. “That baffles me,” Barry says. “With the underhand shot, I could make 80 percent of my throws with my eyes closed. And I do mean closed.” Over the years he has tried to convert everyone from four of his sons who have played professionally to Shaq to Chris Dudley—but nobody has paid any attention. “A lot of guys who are lousy at the free throw would be prime candidates for this, but they just won’t do it,” says Barry, whom the NBA identified as one of the 50 Greatest Players in history in 1996. “I mean, how can guys call themselves professionals when they can’t even make 60 percent of their free throws? Where’s their sense of pride?”
Perhaps that’s the problem with the granny shot. “As good as it is,” Steiger says, “it does look kind of stupid.”
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