These numbers represent the ratio of hitters to setters. In a 6-2 offense, this means that you have two setters on the court and they will transition from back row to utilize all three front row players as the primary attackers. In a 5-1 offense, you have a main setter that runs the offense and when he/she is in front row only has the outside and middle as the front row options.

There are pros/cons to both types of offense. Most teams, utilize a 5-1 because this usually presents a more consistent flow between the hitters and the setter. But on the other hand, if you've got two kick butt setters who can also hit the ball a 6-2 offense may be where it's at!