Baseball players have long used the metal doughnuts to make their at-bat bat speeds faster. Apparently, those doughnuts are doing just the opposite.
Research shows that the doughnuts make players swing the bat slower during actual at-bats, the Wall Street Journal reports.
"As much as possible," Coop DeRenne, a physical education professor at University of Hawaii told the Wall Street Journal, "the batter should mimic in his warm-up what he will do in the game?the same weight, the same motion."
DeRenne said that by either increasing or decreasing the weight, even by just 10 percent, the bat speed decreases from 3 to 5 mph.
Minnesota Twins hitting coach Joe Vavra told the Wall Street Journal that he advises players against using the weights, but understands the psychological reasons that cause players to use the weights.
"A good hitter will say, 'Why should I change what I've been successful at?'" Dale Sveum, the Milwaukee Brewers' hitting coach said.
Of course, doghnuts will always slow your bat speed when you leave them on your bat as you head to the plate, something Philles outfielder Hunter Pence mistakenly did on Monday night in Colorado.