Players work in pairs, sitting on the floor, with a ball between them. Their task it to receiver the ball overhand, pass it high and get up to pass the ball back.
It is easier to make this drill successful if the ball is passed high.
During this exercise body balance is being developed as players have a short time to get up.
New hitters rarely miss because of their arm. They miss because of their feet. Build a reliable approach, then time it with your setter.
When your hitter gets stuffed, five teammates standing and watching is how you lose the point. Good attack coverage turns a blocked ball into a second swing.
Coaches spend hours correcting arms in serve receive when the real fault is almost always the feet. Fix the movement and the platform fixes itself.