Two teams of players behind each goal (6v6) plus goalkeepers in each goal. Two players from one team begin by attacking the opposite goal without defenders. They try to score v the goalkeeper and the moment the ball is shot, two players from the other team launch an attack while the shooter does a press up. The none shooter retreats to a 1v2. The defenders must get back as quickly as possible. 2 or 3 sets of 3 or 4 minutes work well. You can have both players doing a press up or just one and you can vary it with a squat, sitting on the floor or a jump before defending. Attacking team must be ready to attack as soon as the ball is dead. Keep score to make it more interesting.