Sweaty people run laps on an urban side street, dodging forklifts from nearby industries. They go into a warehouse, where they grunt and groan through their weight lifting and conditioning workout at Crossfit Oakland, in Emeryville. Some say CrossFit is a cult. Others, especially post-workout, don’t say anything. They can’t. They’re too tired.

NET PROCEEDS

CrossFit originated in 2000 in a tiny Santa Cruz gym when Greg Glassman began posting his unusual WODs — workouts of the day — online and attracted a following. CrossFit now has 3,400 affiliates worldwide, about 500 in the Bay Area. The brick-and-mortar CrossFit gyms were begun by those virtual fans.

OAKTOWN COLORS

In 2004, Mike Minium, then 32, left a corporate technology job and opened the first Oakland “box,” as the gyms are known. The center attracts a diverse clientele: firefighters, lawyers, Internet moguls, carpenters, academics and employees from nearby Pixar. Workouts like the Danny — named after Sgt. Daniel Sakai of the Oakland Police Department, who was killed in 2009 — commemorate heroes. Others are named for accomplished CrossFitter women: the Cindy mixes pull-ups, push-ups and squats.