FIFA 2012's Impact Engine

the Impact Engine improves collision variety, accuracy, and momentum preservation.A new advanced procedural animation system is used along with collision physics to produce different results depending on the players and physical forces involved. This affects all players, so even those off the ball may have collisions. The Impact Engine has been cited as a game changer, making FIFA 12 less structured and synthetic than its predecessors, and has been described by producer David Rutter as the biggest technological change to the series since the transition to the current generation of consoles. The Impact Engine also directly affects injuries sustained by players during a match. (from : Wikipedia)