This is one of our favorite softball conditioning drills plus it is an great fielding drill. We call it 4 corners.
Two coaches are hitting or rolling grounders. One stands at home plate with a bucket and the other stands at second base (Or closer in with younger kids).
2 Lines of players–one at 3rd base and the other at 1st base. (The players at 3rd and first are even with the coach at 2nd or closer in to keep the 4 corners).
The coach at the plate will hit to the players at 3rd or the glove hand side of players moving from 3rd to 2nd base. As they catch the ball they drop it into the bucket of the coach hitting (throwing) grounders from second. The coach at second will hit glove side grounders to the line of players going from 1st to home and they will drop the ball in the home plate coaches bucket (Helpful to have a parent feeding the coach the balls from the bucket) and each will rotate around to the opposite line. Just keep moving to the next base after dropping the ball in the bucket.
After doing glove side balls the coach at second will hit back hand balls to the players at third that have reversed direction and are heading toward home and they drop the balls in the home plate bucket. The players lined at first will go toward second to get backhand balls form the home plate coach and will drop the ball in the 2nd base bucket.
We also run this for line drives to the glove and backhand side. We throw these balls. We also work on diving with this drill to to the glove and backhand sides.