Some worry 'CrossFit' -- an intense workout regimen popular with adults -- might actually injure children. But trainers say relax; the kids aren't doing the same workout as adults.

Theo Tsekouras, founder of CrossFit H-Town, says this is much ado about nothing.

"Between the ages of three and five; they don't involve any weights -- you never load them up with any kind of weight at all."

Tsekouras says the workout punishes adults with jumps, squats and lifts but it's not punishing for kids -- who clearly need something to offset their sedentary lives.

"I think a lot of people think the kids will have the same intensity of adults and it's just not the case."

Tsekouras says the kids, even as young as five, need the exercise.

"The trend is toward children sitting inside and playing video games and being more anti-social so this really gets them out into the element of having fun and also learning."

Tsekouras says there are five-year-olds who do CrossFit -- but none at his gym.