Football is a game that is full of science. The rotation of a perfectly thrown ball, the forces resulting from collisions between players and the trajectory of a kickoff all make for fascinating topics of study. The science concept we'll talk about today is center of mass.
Center of mass sounds like an easy concept, but it can be difficult to understand. The center of mass of an object is the point where the mass is evenly distributed in all directions; it's also the balancing point of an object. Find a 12-inch ruler and balance it on your finger, and you'll see that it balances at the 6-inch mark. The center of mass of a person is near the navel, but if you crouch or bend over your center of mass shifts. Lowering your center of mass makes you more stable.
Before each play in a football game an offensive or defensive lineman takes a low stance to lower his center of mass. When the ball is snapped the linemen move explosively and crash into one another with great force. Players with a lower center of mass are harder to knock down. When the offensive player has a lower center of mass he can move the defensive player to the side, opening up a hole for the running back. When the defensive player has the lower center of mass he can break through and sack the quarterback.
The same idea holds true in running the football. The running back is usually one of the shortest members of the offense. Because running backs have a lower center of mass than most of the defense they are harder to tackle. Defensive players have to get very low to make a tackle and will often try to tackle a runner by his feet.
In the game of football, physicists and coaches agree -- the low man always wins.