This actually is one of our favorite [tag]softball drills[/tag].   I borrowed it from a former high school coach of mine.   It teaches endurance to your players and how to rally even after they are tired.

Players line up across the field approximately 90 feet apart in a straight line with four in each line (or an even number).
The first player throws the [tag]softball[/tag] to the next player in line then runs to that player’s position and so on down the line.
The last player in line runs all the way back to the front of the line after catching the ball, and the drill starts again until the first player is back in the first position.

When the players get tired, you keep telling them how they are getting tougher and stronger and more accurate–anything POSITIVE to keep them striving for a higher level.   This builds stamina and endurance, and teaches the mind and body to keep going even when are both really tired.

This [tag]softball drill[/tag] has a lot of running and throwing and is a good one to do at the end of practice. I make sure to have plenty of goodies to offer after [tag]softball practice[/tag] as an added incentive!