When the player brings the ball down from above his head he is going to go into the dribble.
Place feet wide apart so the player cannot go past you.
Go two steps back to create a gap and go into a dribble defense mode.
Knees bent, back bent, feet wide and hands down and outwards.
Look wide and intimidating.
Alternate which foot is dropped first.
Do this drill ten times.
This is a quickness drill.
Concentrate on keeping low and quick to create a gap between you and the ball handler so he cannot go around you.
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.
Good spacing is only the start. The best modern offences teach players to attack the defence's rotations and play in a permanent 4-on-3 - here is how to coach that read.
The ball screen produces almost half of all professional offensive possessions, yet most teams still teach it as a memorised play. The modern approach trains the read - giving players a framework to decide based on what the defence does, not what the coach called.