The Boxing Club San Diego, San Diego

The patter of gloves against heavy bags and the paced breathing of circling sparring partners fills The Boxing Club with energy. That's amplified by trainers, who lead classes in everything from cycling to kickboxing. There's muay thai, for example, an MMA fighting style that torches calories with flurries of flying elbows, knees, and fists, or jiu jitsu, which focuses more on grappling.

Martial arts are, in a way, just one more way of working towards physical fitness for many at the studio. Fitness goals are helped along by a full weight room, cardio area, and pilates studio. There's also a full locker room for cleaning up afterwards.