Players work in pairs and stand across the court from each other. One player starts with the ball and overhand passes the ball high in the air to their teammate.
The teammate then overhead passes the ball in the air continuously while the teammate accelerates, runs around the other player and returns to their starting position to receive the ball back, where the teammate will now do the same thing.
The drill makes players run fast, while their teammate has to be aware of the other player running to know when to pass the ball back.
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.