Beef Up or Slim Down
The average defensive lineman at the NCAA Division I level is about 6 feet 2 inches tall and weighs 281 pounds. Depending on the coach's defensive scheme, you may have to gain or lose weight. A coach that prefers a bigger line built to shut down running games may want heavier players. A coach with a scheme based on quickness prefers faster, leaner and meaner defensive linemen. Your weight may also depend on whether you play tackle -- the interior of the defensive line -- or defensive end -- those on the outer edge. Because they are often expected to rush the passer, defensive ends are usually leaner than tackles.
Whether you play tackle or defensive end, the ability to react quickly is essential for effective defensive line play. The goal is to hit the offensive lineman before he hits you. To improve quickness, practice "getting off" the ball. Adjusting your weight distribution based on your stance can improve how quickly you react. Quick-start drills such as shuttle runs can also help improve quickness. The "flip and slip" is an effective drill to improve quickness. Ask a teammate to play an offensive lineman with his arms extended straight out. Exploding off the ball, attack the O-lineman from under his arms. Push him up while flipping your hips toward the backfield. Maintain your balance as you slip by him.
Learn to Anticipate
Knowing where to find holes in the offensive line gets easier if you understand how to read plays. A good defensive lineman can recognize offensive formations to determine the weakest path to the quarterback. By studying film and offensive formations, a defensive lineman can teach himself to anticipate where the ball might be going. This will also help the lineman recognize trick plays and avoid being fooled by ball fakes. Use instinct and timing to disrupt plays. This includes waving your hands in the air to bat down the ball or pushing an offensive lineman back toward the quarterback. Batting down balls and forcing a linemen into the quarterback are almost as effective as a sack.
Get More Aggressive
Defensive linemen must possess an aggressive approach to controlling the line of scrimmage. The line is no place for the timid. Aggressive linemen put pressure on the quarterback and make life easier for defensive backs who are responsible for guarding receivers. Leverage size, speed and quickness to thwart pass blockers. Although aggression is mostly an attitude, a more aggressive style of play can be taught and incorporated into the coach's scheme. The key is to remain in attack mode. Be relentless.
Perfect these basic pass-rushing techniques to dominate offensive linemen: the shoulder drive, quick drive, counter and bull rush. Use the shoulder drive to push an offensive linemen back and into the quarterback. Using your inside shoulder, thrust up and into the blocker's outside shoulder, pushing him back. In the counter move, you fake rushing the quarterback and, with a quick jerk, move the blocker away from the position you plan to attack. Use the quick drive — sprint off the line to an opening — to exploit slow blockers with poor footwork. The easiest move is the bull rush. Explode off the line, extend your arms and plant the palms of your hands right into the tackle's numbers.