Ilaria Montagnani and Pat Moreno, who began choreographed martial arts/aerobics-fusion classes called Power Strike more than two years ago, must be kicking themselves for not marketing the hell out of a video now that Tae Bo has practically spawned a national cult. Hear the meekest of women emit grunts and yells as they deliver uppercuts and roundhouse kicks at Reebok (160 Columbus Avenue, at 67th Street; 362-6800). Gotham Box, at all Equinox locations (897 Broadway, near 19th Street, is a good one; 780-9300), is another wildly popular Tae Bo-style workout that exhausts a variety of muscle groups. If you hit the Thai Boxing class at Revolution Studio (104 West 14th Street; 206-8785), you might just see Puffy Combs warming up for his next round with a record exec. Make sure to leave a buffer zone of space around your body so you don't find yourself impaled on your neighbor's flailing limbs.
If you know your right from your left and can handle twirling around a bench with the speed of Darci Kistler, there's Laura Cozik's Cardio Step class at the Broadway and 19th Street's Equinox. And step classes taught by Calvin Wiley at Crunch (55 East 13th Street; 475-2018) might embolden you to try out for Fosse. The challenging footwork in both these classes keeps your mind off the physical strain and actually makes the hour fly by (you might want to bring along earplugs, however). Duant Cooley's Pump 'n' Grind at the East 13th Street Crunch is a "toning" session set to hip-hop music that is so fast-paced -- you go from the floor to a step, to a body bar, to weights -- that your heart could easily confuse it with what's usually billed as cardiovascular.
Strutting moguls and the models they chase are at last on the same side of the playing field at the Madison Square Club's outdoor Fitness Drill classes (210 Fifth Avenue, near 26th Street; 683-1836). It's Us (weekend warriors) against Them (sadistic trainers) as the pros push small groups through "cardiosculpting" sprints, bench dips, and step-ups in the park. Club owner David Kirsch is nicer than any P.E. teacher you've ever had -- but twice as tough.