Pogopalooza 6 promises to challenge the legs, knees and daring of 50 skilled pogoers, all while observers' heads bob up and down to witness the action.

Saturday afternoon in Schenley Plaza in Oakland, Pogopalooza 6 will feature world-class pogo athletes from the United States, Canada and England who will compete in such events as the high jump, best run, best trick and least jumps per minute.

To promote the big event, demonstrations are scheduled throughout the city today and tomorrow.

And, for sure, this isn't your child's pogo stick.

Participants will use extreme pogo sticks, including the BowGo, which was developed by Ben Brown of Carnegie Mellon University and a source of considerable excitement among pogo athletes.

There are expectations that pogoers on BowGos, with some mojo, will clear 9 feet in the high jump. Also expect flips, gymnastic maneuvers and in-air acrobatics.

"This is related to extreme sports, but it's also related to entertainment, fitness and fun," said Nick Ryan, 20, a Pogopalooza 6 organizer and incoming junior at Carnegie Mellon University. "The BowGo is a huge addition to this world."

Mr. Brown, a 64-year-old project scientist, had been working on robot mobility by using curved fiberglass legs when he decided to use a similar design to create a pogo stick. His BowGo uses fiberglass that bows out under body pressure when the stick hits the ground then propels the rider to great heights when the stored energy is released.

Over the years, he's improved the design, efficiency and durability of BowGo while improving the fiberglass bow. The result is an instrument that tests the limits of pogo-stick technology, which had seen no real advances beyond the steel-coiled spring from 1918 until the mid 1990s. Modern extreme pogo sticks produced by Vurtego, XPogo and Flybar now use air pressure and rubber bands to gain new heights.

But these aren't toys. Instead, the extreme pogo stick require rider skill to power and control it and prevent serious injury.

All Pogopalooza participants wear helmets. Six use the BowGo on Saturday to try to break world pogo records.

Mark Aldridge, 17, of Crowthorne, England, a premier pogoer in the British Isles, tried out BowGo for the first time Tuesday and described it as "excellent."

"This will be used to jump higher and do bigger things," he said.

Mr. Brown uses a smaller BowGo that lifts him about a foot off the ground. Still, over the years, he's cracked ribs and has been found unconscious several times on the floor. Mr. Ryan also cracked his ribs, broke a leg, and blackened his ankles. His worst accident occurred four years ago when he was paralyzed for a month.

Mr. Brown said he could create a more powerful BowGo, but "it's already getting scary." The latest version requires 1,200 pounds of compression to produce full propulsion.

His invention is the reason why Pogopalooza 6 -- the sixth annual competition for pogo athletes -- is being held this year in Pittsburgh.

Performers will include The Pogo Dudes -- three pogoers from Ohio and New York whose demonstration includes comedy routines. Along with Mr. Aldridge, Dan Mahoney, an upcoming extreme-pogo star from Truro, Nova Scotia, also will compete and perform.

Demonstrations are scheduled noon to 2 p.m. today in Point State Park with pogoers scheduled to hop their way through the Downtown from 2 to 4 p.m.

From 1 to 4 p.m. tomorrow pogoers at the Carnegie Science Center on the North Shore will demonstrate their skills and discuss pogo science. Then, from 8 p.m. until dusk, they'll provide a photo shoot near the observation decks on Mount Washington beside the Duquesne and Monongahela inclines.

They hope the demonstrations give a bounce to Saturday's competition in Schenley Plaza, between the Carnegie and Hillman libraries in Oakland.

John Tanner, founder and chief executive officer of Tanner Research Inc. in Monrovia, Calif., said Mr. Brown's BowGo has potential. He informed Razor USA about Mr. Brown's invention, and the Cerritos, Calif., company that makes scooters and toys now is working to produce a scaled-down, safer version of BowGo for children.

"Some of our riders have exceeded the world-record height," Dr. Tanner said. "Other manufacturers are not sitting still, either. It will make for a very interesting competition."