When you have possession of the ball and the opponent is trying to chase it, you have to shield the ball if you cannot immediately pass or take the shot.
Depending on your position and the situation, there are different ways to shield.
Playing a five out defense is making the sport spectacular, fast paced and very interesting, but the tactic is tricky, though, exhausting and not easy to master.
Most teams only play it when they are behind and need to press the ball. Both with and without shot-clock, this defense is key to keep up the pressure and make up for some lost time.
