I CAN’T STOP watching my feet. I’ve spent the past 15 minutes jumping up and down on a mini-trampoline, and each time my body rises upward, my eyes gaze down. If I don’t do this, I worry that my feet will land on the very edge of the tramp’s surface, I’ll lose my balance, and I’ll tumble off.
It’s a new and uncomfortable feeling, but so is just about everything about my Bounce Essentials class at the Ness, a New York City group-fitness studio that focuses on a unique implement, the minitrampoline, which is about
