LOS ANGELES, Oct. 13 (UPI) — Curve balls don’t “break” and fastballs don’t “rise” despite long-held baseball beliefs, U.S. researchers say.
A study by a group from the American University and the University of Southern California proved it’s an illusion, but one that can make it hard for a batter to connect with the ball, PhysOrg.com reported Wednesday.
“The curve ball does curve, but the curve has been measured and shown to be gradual,” Arthur Shapiro of the American University said. “It’s always going to follow a parabolic path. But from a hitter’s point of view, an approaching ball can appear to break, drop or do a whole range of unusual behaviors.”
An apparent sudden drop or other change in trajectory as a pitch approaches home plate is an illusion caused by the shifting of the batter’s eye between central and peripheral vision, another researcher says.
Batters tend to switch from central to peripheral vision when the ball is about 20 feet away, or two-thirds of the way to home plate, Zhong-Lin Lu of the University of Southern California says.
The eye’s peripheral vision lacks the ability to separate the motions of the spinning ball, Lu said, and it gets confused by the combination of the ball’s velocity and spin.
The result is a gap between the ball’s trajectory and the path as perceived by the batter.
As the ball arrives at the plate, the batter switches back to central vision and suddenly the ball seems to be in a different spot than expected.
That perception of an abrupt change is the “break” in the curve ball that frustrates batters, the researchers say.
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