When scrumming your forwards bind against their opponents in a mass of bone and muscle. The force of 16 players pushing against each other makes breaking from the scrum difficult. A good clean break off the scrum can give your loose forwards that few extra meters in attack and defense.

The loose forwards (6,7,8), because of their position in the scrum and 'loose' binding are able to break from the scrum far quicker then their 'tighter' team mates.

To represent this fact apply the following rule. In the turn that you win a scrum your players 1-5 may not be moved. They must remain in the same position that they formed the scrum.