It all starts up front.

For many casual football observers, that phrase instantly conjures an image of the offensive line striding toward the ball.

But football coaches know that approach and technique are just as important along the defensive line, where players must navigate stunts, double teams and everything else to get their jobs done.

SEE ALSO: Watch all of USA Football’s Skills and Drills videos for defensive linemen

Antoine Smith, defensive line coach at James Madison University, recently shared on Stack.com the five characteristics he looks for in defensive linemen. Every drill he installs works at least three of these traits.

• Quickness. A defensive lineman must demonstrate quickness in his ability to move in all directions. He should demonstrate an above-average reactive ability for his size.
• Flexibility. A defensive lineman must demonstrate extraordinary flexibility for his size. Flexibility is a requirement for maintaining the proper leverage as he defeats blockers.
• Power. The defensive lineman must be able to strike a blow with power. He should have a knack for delivering an explosive blow to the opponent. He cannot be a leaner. He must be able to quickly shed a blocker.
• Recognition. The defensive lineman should be able to make the proper adjustments and adapt to changing situations. He has to be able to recognize offensive blocking patterns quickly and respond with an immediate physical action.
• Consistency. The defensive lineman must demonstrate reliability and consistency under pressure. He should respond to his reads properly at all times. He should demonstrate a football IQ in that he is able to relate to down-and-distance tendencies, field position tendencies, clock factors, time remaining and formation tendencies.