Tracy Gates smiles wide and kicks off her high-heel shoes under the desk in her office.

Children's drawings and hand prints hang on the wall. Photos of her daughter Sunshine, 6, and son Joel, 4, and a potted plant decorate a side table.

Not quite a scene to strike fear in your heart.

But if you saw Detective Gates later, punching the air, and kicking an imaginary door or assailant during her body combat exercise class, you may just feel differently.

"Harder," she yells. And kicks and jumps as sweat beads on her forehead.

Gates, 29, investigates crimes against property, and teaches exercise classes at Gold's Gym six days a week.

"I love it, I feel good about myself," she said. "I know if I get put into a situation, my fitness level is not going to be an issue for me."

At work, she investigates burglaries, theft, criminal mischief and damaged property. At Gold's she teaches body combat, body pump and RPM.

"She's tough," says co-worker Kimberly Scalf, who takes some exercise classes.

Gates, who earned a bachelor's degree in sociology from Abilene Christian University, enjoys the interaction with people in the gym.

"Everything is not so serious. It's fun and it's a workout. You get to hang out with people that have the same goal as you: change their bodies and change their lives."