OAK CREEK-- Slamming weights, intense drills, and military style training-- it's what many people picture when someone mentions CrossFit. As the CrossFit craze gains momentum in Wisconsin, children are joining their parents at the gym.
For Jacob Young, a seventh grader, it's about conditioning for football, basketball, and baseball.
"We're getting stronger and having fun at the same time," said Young.
Young has been doing CrossFit for Kids for more than a year. His father, who coaches him in football, says CrossFit has improved Young's performance during games.
"People were like, you're in seventh grade?" said Young, laughing.
Not everyone in CrossFit for Kids is a middle school or high school athlete. The classes cater to all fitness levels, some children as young as four, including Sandy Ahlensdorf's son.
"As soon as he turned four, and they started to offer classes here, he was ready to go," said Ahlensdorf.
Getting kids moving is a good thing-- but medical professionals say parents should be careful.
"As kids grow, your bones are actually weaker than what your muscles are," explained Travis Vande Berg, a physical therapist at Children's Hospital in Milwaukee.
While adults can strain muscles-- Vande Berg says children could suffer bone injuries if they use too much weight during their work outs.
"Kids as they're growing tend to actually rip the bone away from the bone," he said.
Maggie McNieve owns Cross Fit Oak Creek, with a nursing background-- she's extra careful with her students.
"For our youngest kids, they usually don't use load at all," McNieve explained, "they just use an 8 ounce PVC pipe and they're just working on form, or no weight at all"
As a parent-- she makes sure each exercise is age appropriate and many parents agree.
"I never look over and see my son lifting a heavy barbell," said Ahlensdorf, "it's always something that is age and body appropriate."
McNieve says at the end of the day-- her class is about keeping kids healthy.
"Children it's all about fun and keeping them moving," said McNieve.
Vande Berg and McNieve both agree that all gyms are not created equal. They say it's important for parents to check a fitness instructor's credentials and observe classes before enrolling their children in any fitness activity.