The coach (F) is ready to feed from the basket, about halfway between the service line and baseline.
The players form two lines behind the service line, with the first player in each line stepping inside the service court.

Drill:
The coach feeds alternating to the first two players (A and B) lobs. After each overhead, the players will run up to the net, tap it with their racquets then back up for another overhead. 
Each time a player hits an overhead in, they count it. 
The first player to hit 10 overheads in, then both players exit the court making room for the next two players (one from each line to step up inside the service court). 

Notes:
- Moving up to tap the net after each overhead and backing up to execute it makes it for a good workout.
- The waiting players can perform various exercises: jumping jacks, ladder exercises, cone drills, etc.