
This drill isolates the backbone of the defense: the CHASER, the MIDDLE, and the TAIL. These three must move in unison as the ball moves about the perimeter. Four players are positioned around the perimeter with two additional players on the low blocks. The perimeter players move the ball randomly while the defenders practice their coverage responsibilities.
Source:https://www.breakthroughbasketball.com/defense/131-zone.html
This practice has no coaching points
This practice has no progressions
Four players standing still make every ball handler's job harder. Teach V-cuts, L-cuts and back cuts so your team gets open and punishes defenders who overplay.
Good team defence is five players guarding the ball, not five separate one-on-ones. The shell drill is where that starts, so here is how to teach help-side positioning and rotations from the first week of the season.
Rebounding is the least glamorous thing in basketball and one of the most decisive. It is also almost entirely a habit, which means it is entirely coachable.