Get the breakdown on coaching defensive line in the 4-3 Defense. Alignment, Stance, Key Reads and Assignment. The Miami 4-3 Defense is a great system for defenses that have the right athletes. One of the features is the simplicity and aggressiveness in the Defensive Line play. We’ll break down the ASKA for coaching defensive line play in this great defensive front. Alignment, Stance, Key Reads and Assignments for your base 4-3 Defensive Line.