Two players working together to block a smash from an opposition player.
Both players jump at the same time as the opposition 'Smasher', keeping hands high and parralel to the net.
Keeping eyes on the 'smasher' at all times throughout the block enables possible position changes at the last minute.
New hitters rarely miss because of their arm. They miss because of their feet. Build a reliable approach, then time it with your setter.
When your hitter gets stuffed, five teammates standing and watching is how you lose the point. Good attack coverage turns a blocked ball into a second swing.
Coaches spend hours correcting arms in serve receive when the real fault is almost always the feet. Fix the movement and the platform fixes itself.