The 4 players inside the blue square must protect the square and stop the ball carriers entering.
To begin with the players inside the square are only allowed to shadow and block the outside players from entering.
One point is scored by each player who successfully carries out their objective.
If the defender wins the ball then the players switch roles.
Adopt a surf position when defending, mirror the attacker and try to channel them away.
Players inside the square are allowed to tackle the other players.
"It is not only useful for staff who are experienced but a valuable tool for those subject staff who have to take teams."
The variety of sessions across sports - sometimes we steal session ideas from one sport and use them with another.
As we enter the business end of the competition, we take a look at the remaining eight teams and the key talking points surrounding each side.