They come to the gym for about an hour, but it really all comes down to roughly 10 minutes.
Ten minutes of what participants call the most grueling workout they've ever put themselves through.
"It's the hardest thing I've ever done for a workout," said Woodbury resident Mike Koeplin.
He and his son Cody were participants last week at CrossFit Woodbury. Owner Matt Burns, a fitness expert who specializes in the CrossFit program, which is geared toward athletes, opened the gym in October.
The business is located at 680 Commerce Drive, Ste. 110.
Once gym members arrive, they spend about 45 minutes warming up and practicing the exercises they'll be put through later in the session.
When the group workout starts, participants are up against the clock to log an intense series of repetitions blending weights and other exercises.
"When that thing goes off, the intensity goes up," Burns said, gesturing to a digital clock mounted to the gym's cinder block walls.
The CrossFit program develops 10 categories of physical fitness, Burns said - everything from strength and stamina to balance and accuracy.
Burns entered the fitness world in 1979 as a martial arts instructor in San Diego. He later spent time in the armed forces before spending 20 years as a firefighter.
He said he picked up on the CrossFit program three years ago and was instantly hooked.
"I was just blown away," Burns said. "CrossFit is really, in some ways, really redefining fitness."
After working as an instructor in California, he decided to take a step to the next level as a business owner when he and his family moved to Minnesota last year.
So far, the payoff has been rewarding, he said.
"You are helping people on many levels," he said.
Burns admits the workouts are demanding.
"It's not for everybody, but everybody can do it - you've just got to want to," he said.
Koeplin's son Cody, 10, said he can't get enough of the program's rigor.
"It's the hardest workout I've ever done," he said.