ORLANDO, Fla.  The art of flinging a yo-yo is almost unrecognizable to those who have not seen it done well in the past decade or so. At the recent World Yo-Yo Contest here, it was immediately obvious that yesterday’s forgotten up-and-down string toy is today’s “extreme sport you can carry in your pocket,” the yo-yoer Andrew Arvesen said.

The seven championship disciplines  six more than when the annual contest began in 1992  have nothing to do with walking the dog or rocking the baby. Some yo-yos are tied not to fingers but to counterweights like casino dice or rubber balls. Some yo-yos are flung intentionally from their string and are recaptured by nothing more than friction and a magician’s timing.

The competitions are frenetic three-minute routines filled with tricks performed too fast to make sense of them all. The best bring the knowing fans to their feet, and will be seen and imitated by thousands, maybe millions, who watch the replays on the Internet.

If that is not enough to demonstrate just how much things have changed for the yo-yo, consider that a title contender from Singapore dislocated his knee during a preliminary round and was taken away in an ambulance.