Do you know that volleyball is the most widely spread ballgame in the world??
Even though football is known by the people as the most popular ballgame in the world, volleyball is the most widely spread game if it is measured by the number of the countries participated as a member at international head organization (FIFA soccer has 209 while FIVB volleyball 220). FIVB declared statistically that there are over 500 million people around the word who practice and participated organized volleyball and beach volleyball.
Why should we update our knowledge with the new researches in volleyball??
One of the biggest problems that cause the lack of improvement in volleyball performance in the fact that coachers use the same methods as they have experienced when they were players. These lead to an old concept of volleyball and thus continue keeping the traditional methods of playing. Few countries have approached the new idea comes from scientific researches by imitation and not by coaches influence. The method of imitation is quickly spread to the other players and teams when it has worked.
Vuorinen Kasper, 2017. Modern volleyball analysis and training periodization.

https://www.semanticscholar.org/paper/MODERN-VOLLEYBALL-ANALYSIS-AND-TRAINING-Vuorinen/171474710c000c9db0912c0110fe236ad9350ba0