Brianna Parker breaks her very first pine board with the heel of her hand Thursday at Rick Hall's Tiger Rock Martial Arts in Hixson.

Pine boards beware: You are on the chopping block for students of Tiger Rock Martial Arts.

Students and instructors alike are able to use the heels of their palms, their elbows and their feet to break 1-inch-thick pine shelving boards, sometimes stacking them three or four deep, but they don't do it to show off.

The Hixson Tae Kwon Do academy uses board breaking to test a student's readiness to advance to higher ranks. As students progress to higher belts, they are required to break boards as a means of testing their technique's focus, power and accuracy.

It is not a test that Grandmaster Rick Hall, an eighth-degree black belt and the academy's owner, takes lightly.

"We are using real, legitimate self-defense techniques," he says when talking about why board-breaking is performed. Unlike some academies where boards are bolted to the wall or supported with cement blocks on the floor, Tiger Rock Martial Arts instructors hold the boards. That means the instructors move naturally with the force of the blow just as an opponent might.

"You've got to hit the board exactly in the center, you've got to hit the board with enough velocity to break it before it knocks the holders away, and you've got to hit with enough acceleration and power to smash the board," Hall said.

Younger students might start with small boards, only a few inches in length, while adults begin breaking 12-inch-long boards. As students move up in rank, the boards are stacked together, which exponentially increases the difficulty of breaking them. The force required to break a stack of three boards is roughly equivalent to the force necessary to break a human femur, Hall said, though that is not what Hall and his academy are encouraging with these techniques.

The academy is concerned with instilling a combination of mental and physical discipline in students.

"It hurts when you break those boards," Hall said. That fosters mental strength to accompany the physical strength the student possesses.

"For a moment there, you are totally engaged in the process of breaking that board, mentally," he said. "The more your mind and body learn to work together, the more capable you are in many aspects of your life outside the martial arts academy."