David Slick, a student at Dallas Baptist University, juggled the tennis balls for 12 hours, 12 minutes and 12 seconds, besting the previous record of 11 hours and four minutes, the Fort Worth (Texas) Star-Telegram reported Monday.

"I knew I could do it. I knew it would be hard. But I knew it would be worth it," he said.

Slick, whose name will now be printed in the "Juggling Three Objects Nonstop" category of the Guinness Book of World Records, said he practiced for his record attempt in his dorm room.

"You wouldn't believe how sore you could get just throwing some tennis balls up in the air," he said.