This is one of the basic basketball drills that can be used to teach defensive positioning for each defense that you play, regardless of whether it is man to man or zone. Any type of man to man defense can be taught through variations of the basic shell drill.
In this case, we are using pack-line rules, so there is no denial of perimeter passing. You can modify the drill in order to include denial of permimter passes if that is the defense you play.
Once you have the basic movements and defensive spacing taught, the drill can be altered to include helping on dribble drives, playing cutters, double teaming a post feed and rotating out, defending flare or down screens, defending ball screens, and any other offensive scheme you need to prepare for.
One key basketball coaching point that is illustrated in the video is to teach the defenders to run when the ball is in the air and arrive with a closeout in their assigned defensive position when the ball is caught.
Other Pack Line Defense Resources
Here is a vodeo clip that is around a minute and 45 seconds of Sean Miller discussing a part of their scheme for defending the post. Sean Miller Defending the Post. The Xavier men play a pack line man to man defensive style and this is how they defend the post.
Defensive drill working on chasing a cutter through a screen from Coach Dick Bennett. The link will take you to the page on the Championship Productions web site where Coach Bennett's DVD The "Pack-Line" Pressure Defense is outlined. Additionally, you can read reviews of the DVD. Scroll to the bottom of the page to see the video of the drill.