The biggest rule change in NBA history happened in 2001.. and many don't realize

Many people out there don't realize how big of an impact the end to the illegal defense rules in 2001 had on how the game is played.

Let me explain what illegal defense was. In simple terms without getting too complicated, each player had to guard his man and could not help out his teammate by coming off of his man and guarding an "area". Today, defensive players can play wherever they want. They don't have to specifically guard their man. Their man can be all the way on the other side of the floor and it's legal.

Here is an example of a Charles Barkley post-up. Look at how the illegal defense rules cleared out the floor:




Look at the lines I drew. Player #1 and player #2 are not allowed to go below the red free throw line I drew because their men are above the 3 point line. Players #3 and #4 cannot go into the lane because their men are far away on the weakside. The only way they can go into the paint is when their man is within arm's length. Look at how much freaking space Charles Barkley has to go 1-on-1:





Here is a clip of Jordan:


Notice #5 John Paxson at the top of the key pointing at his defender. He's trying to tell the ref he's below the free throw line and it should be illegal defense. (He is allowed to double team, but he has to commit to Jordan... he cannot hop back and fourth between both men like he was doing). And look at how much space Jordan has to go 1 on 1. No help defense in the lane. Look at all of the help defenders having to stay on their man while Jordan backs his way in. That's how the rules were.



Another clip of Jordan:


In this clip, look at the white Bulls player at the bottom of the screen. Look at how he points to the Lakers player who is in the paint. He's trying to signal to the referee that he's illegal. Look at the other help defenders who are right on the edge of the paint. They have to be there and it gives Jordan a ton of room. He just has to beat his own man and nobody is there to stop him. Because of the rules opening up the paint, defenders are too slow to stop the jam. And keep in mind that the defender who was too slow was actually illegal... he should have been even slower.






Now, let's look at how that compares to today.



Look at how low David Lee is in the paint. He's in the middle. Harrison Barnes leaves his man and cheats into the middle to help Andre Iguadala. All 3 of them contest the shot. Much different from the space players got before the rules change.



Once Kevin Durant beats his man, both Andrew Bogut and Klay Thompson are waiting to help. They are playing in space off of their man waiting to help. And Curry is in the lane while his man is all the way in the corner. Players now are allowed much more freedom to play in space to stop the ball.





These are the reasons why the post-up game is going extinct, and it's become more of a guard-driven shooter's game.

Players can protect the paint now like they couldn't in the past.

So when you criticize players for shooting too many 3's and not posting up enough, now you know why. The rules dictate how the game is played.

Great 1-on-1 isolation players have it much harder today because isolation today isn't so isolated when other defenders can step up and challenge.