Upon entering Go Cycle Studios, it might feel like you’ve accidentally walked into a club: hip-hop, rock, and dance music streams from the expansive sound system, reverberating off the exposed brick walls and polished concrete floors. The cycling and fitness center’s owners, Jimmy and Lisa, use this atmosphere to set the mood, but they’re serious about exercise. They and the other instructors tailor spin classes and other fitness programs to challenge riders of all levels, from beginners to those who want to work up to jumping a police barricade. Under their instruction, riders sweat astride Keiser stationary bikes, each outfitted with monitors that display RPMs, heart rate, approximate calorie burn, and miles covered. Before or after class, students can head to the back patio to sip coffee in the fresh air or furtively discuss ways to hasten the comeback of handlebar streamers.