Believe it: LOGROLLING is hot. The annual Teva Mountain Games, in Vail, Colorado, demo'd the sport last summer, and now you can join a rolling class at dozens of pools and lakes nationwide (see uslogrolling.org). Plus it turns out that balancing on a floating 12-foot cedar log builds core strength and cardio endurance while giving you quick feet and (naturally) tree-trunk legs. Get started with this crash course from 2004 world champion Lizzie Hoeschler—and leave the suspenders at home.

1. The only required gear is flexible, grippy footwear. Use kayak shoes, like Teva's Gamma Pro or Nike's Aqua Sock.

2. Have a friend hold the log as you climb on. Once up, keep your knees bent at about 45 degrees and lean forward slightly at the waist. But don't crouch so much that you can't move your feet, which should be hip width apart.

3. To roll properly, move your feet up and down like pistons (imagine squashing bugs). This isn't a treadmill. Expect to fall—a lot. Never try to catch yourself on the log; when you start to go, push away from it with your feet.

4. The arm closest to the center of the log should be extended back; the other arm forward. Keep both arms relaxed—your balance and power come from the waist down. Waving your arms and swaying your upper body will throw you off.

5. Don't look at your feet. Instead, focus on the far end of the log to improve balance.

6. Expect to fall—a lot. Never try to catch yourself on the log; when you start to gom, push away from it with your feet.

7. When you're ready to go head to head with another roller—you'll need at least several sessions of solo practice first—try this move: Wait until his feet slow down, then give a quick sprint. And gloat only after he's in the drink.