1 Introduction.

Association football, more commonly known as simply football or soccer, is a team sport played between two teams of 11 players with the use of a spherical ball. An estimated 250 million players active in over 200 countries and dependencies makes it the world's most popular sport to date. The game is played on a rectangular field called a pitch with a goal at each end. The objective of the game is to score more goals than the opposition by moving the ball beyond the goal line into the opposing side's goal in the time frame of 90 minutes plus stoppage time and occasionally also extra time.