Mike Lupoli's dyslexia nearly derailed his academic career. When he was in sixth grade, his school principal, unaware of his handicap, cautioned him not to consider college. Lupoli disregarded that warning.

"I had to work a little harder," he says, "but I graduated with honors."

For the last 19 years, Lupoli, 56, has been a phys-ed teacher at Sabold Elementary School in Springfield, Delaware County. He believes his dyslexia has proved a professional advantage that has enabled him to contribute to the well-being of his youthful charges.

"Most people who are dyslexic are usually very good at imagining or visualizing how things work," he says. "I've been told that what I do is very creative, but it really comes naturally to many dyslexics."

Proof of that assertion has been on display at Sabold Elementary for the last week. The gym has been converted into what Lupoli calls the Indiana Jones Adventure Course.

"Imagination is intelligence having fun," a sage once observed. It appears to be Lupoli's operating principle, and the fourth graders I observed one morning gleefully scampering through the course with boundless energy certainly seemed to subscribe to the sentiment. They were getting plenty of exercise, but it was the healthy byproduct of loads of fun.

Lupoli, a longtime fan of obstacle courses, has designed a doozy, continuing a tradition that began in 1993. As the theme from Indiana Jones played in the background and movie clips flashed on a screen, the irrepressibly kinetic Sabold students swung on a rope over the Anaconda River, teeming with imaginary lethal snakes. They tiptoed on a balance beam over Great White Shark Inlet. One false move and they'd be human hors d'oeuvres!

They swung on rings over a river of red-hot lava, then did forward rolls over a mini-volcano. Gingerly, they advanced along a swaying rope bridge, then climbed to a narrow ridge atop an eight-foot wall, inching their way to a culminating precipice. There, they had no choice but to leap onto three large mats staggered as steps that carried them into the path of a swinging "25-ton" boulder, six feet in diameter. If they were struck, they had to take a timeout to recover from their "concussion."

Elsewhere, they had to scale an inflatable mountain, 15 feet at its peak, then slide head-first down the other side.

"It's totally awesome," said Ken Everett, 10. It "makes you stronger and gives you a better sense of balance."

Presiding over the merry chaos was Lupoli, dressed like Indiana Jones in a fedora and leather jacket, with a fake tarantula gripping his chest.

"The idea is to make phys ed more fun," he said. "If you go around an ordinary obstacle course 25 times, it's boring."

It is particularly popular with special-needs students, who with accommodations enjoy it as much as any others, he says.

The obstacle course is set up for a week right before the spring fair, which occurs on a Saturday. Such is his devotion that Lupoli shows up to supervise, volunteering his time on his day off.

"Because kids spend so much time in front of a screen these days, Mike has done an outstanding job of creating a way for them to use their bodies and imaginations," Sabold principal Cindy Mattei said. "Kids who are reluctant to try some of the tasks become so wrapped up in the imaginary drama that they don't have time to become self-conscious and worry about the physical challenges. They just do it."

Every year, she said, Lupoli "tweaks it a bit [this year, students were on the lookout for artifacts, jewellike charms, and such] . . . . Many graduates of the school come back during the spring fair for the sole purpose of trying Indiana Jones again."

This year, for the first time, using gym mats, the balance beam, and parachutes, Lupoli created a 115-foot-long "cave."

Student spelunkers negotiated the dark cavern with flashlights and headlamps. Exclaims Lupoli, unnecessarily: "They loved it."