RowClub, San Francisco

Inside its 1,200 sq. ft. studio, RowClub delivers a whole-body workout using the humble rowing machine. The continual rowing action constantly challenges bodies over 45 minutes, combined with functional movement and core strength training. Those who don't know much about rowing can simply ask one of the trainers to help them out, which won't be a problem, as they've helped more than 3,000 exercisers get started over their five-plus years in business.