Blocking is not learned by all players since only the front row utilizes it. However, it is the main defense against the opponent's attacks and helps to slow down the speed of the attacks to make it easier for the back row to pass.
Blocking can be done by one to three players. There are single, double, and triple blocks in volleyball. The concept behind the three blocks are all the same.
Each blocker needs to:
Single Block - where one person blocks the spike. This is usually not effective enough to stop a spike but is more of a way to help the back row pass better.
Double Block - where two people block the attack of the opposing team's hitter.
Triple Block - where three people come together to block a spike. This is usually the most effective and powerful since there are more hands to cover more surface area.