Carr climbs onto the platform. Cameron begins his swing. Carr launches. He flies out parallel to the net on the front end of the swing. His body forms a seven on the back end. Back and forth he goes. Then he twists, tucks, and -- "Hep!" -- releases, right at the moment that Cameron is at the front of his swing. In a flash, Carr is in Cameron's grip. The cat is caught.

Change Trick: If Your Change Effort Isn't Working, Change It

After three years of relentless practice, Derek Bosch, a soft-spoken graphics software engineer at SGI, traded the trapeze for the trampoline, an apparatus that he describes as being "friendlier." An ace juggler who can keep five balls in the air at once, Bosch is Mr. Medium -- in height, weight, and coloring.

Whereas a lot of fliers are risk takers who function best when the adrenaline flows as plentifully as the lattes, Bosch took up flying precisely because it's the kind of thing he never imagined doing. In a sense, he was looking for a change that he couldn't quite envision.

"I'm a bit of a chicken," he admits. "Prior to flying, my biggest challenge was tennis. I took to the trapeze because I wanted to shake myself up."

At first, just climbing the ladder qualified as a thrill in Bosch's book. Few moments, he says, are as gloriously terrifying as the first time you stand with your toes hooked over the edge of the platform, psyching yourself up to leap into the waiting arms of gravity.

"I have a healthy fear of heights," he concedes. "Standing on the platform is harder for me than working the trick. People used to give me a hard time about that."

But oddly, fear wasn't the reason that Bosch made the switch from trapeze to trampoline. While flying is exhilarating, it's got a steep learning curve. It's not unusual for people in the more advanced ranks -- recreational fliers as well as professional trapeze artists -- to take half a year to perfect a single trick.

"I hit a vast, flat plateau," he says. "I worked on the same trick -- a half turn -- for nine months." It looks simple enough: Take off from the platform in the normal position, then twist and switch your hands at the front of the swing, so you're facing the platform when you return to it.

"But I just couldn't nail it, and I really got frustrated," Bosch continues. "I want to feel that I'm progressing, so I did the unheard of. Even though I loved it, I walked away from the trapeze. I needed a change."

I watch Bosch during his warm-up. He hits 45 consecutive jumps, straight into the trampoline's sweet spot: 15 tucks, 15 straddles, 15 pikes. At the top of one of the jumps, he throws his legs out behind him, dropping face-first into the trampoline. This is a front drop, which most people avoid because every instinct tells you to put out your hands to break the fall. But Bosch prefers the front drop to the less-risky back drop. "I always like to see where I'm going," he deadpans.

Even though he's scaling the heights on the trampoline, Bosch hasn't quite cut the cord on flying. "The trampoline is a great way to reduce work stress. It takes a lot of discipline to jump well, which forces me to get my head out of my job. But unlike flying, jumping isn't life altering. Since I've been flying, I've also gone bungee jumping and hang gliding -- stuff I never would have attempted if I hadn't taken up the trapeze."

Bosch has resolved to get back on the trapeze by the first of the year. "Just thinking about it," he says with a grin, "freaks me out."

Karen Karbo (kkarbo@aol.com) is a contributing editor at Condé Nast's "Women's Sports & Fitness." Her forthcoming novel, "Motherhood Made a Man Out of Me," will be published by Bloomsbury USA.

Action Item: Fly by the Book

In his recent book "Learning to Fly," author Sam Keen flies high by tracing the spiritual benefits that can be gleaned from swinging aloft on a trapeze. Keen, formerly a contributing editor at "Psychology Today" magazine, leavens his enlightenment with unlikely tales of his own struggle to master the trapeze at age 61. Even for the philosophically disinclined, "Learning to Fly" is the best book written by a recreational flier.

Coordinates: $23. "Learning to Fly: Trapeze -- Reflections on Fear, Trust and the Joy of Letting Go," Broadway Books, www.broadwaybooks.com