Defense is broken into 4 different types. On-ball defense, off-ball defense, help-side defense, and post defense. The MOST important detail in any type of defense is to understand that motor and focus are needed EVERY second the other team has the ball. The second you lose focus or motor, the other team has an opportunity to score. Teams run offenses based on the idea that someone will get tired or lost on defense. The second you do, that’s when they’ll beat you.
From a technical standpoint, the most overlooked detail of defense is that the lowest man wins. In a low athletic stance, you are stronger than opposing players standing up and you are also quicker and more engaged. In the post, help or on-ball, if you are always in a low defensive stance, your defense will immediately improve.