re: Landon Collins gets trucked

It's a simple matter of physics. Two objects collided, and energy was transferred. The running back had more kinetic energy due to his greater velocity at impact, and the running back hit Collins with enough force to cause Collins' center of gravity to move to where it became unstable and Collins was knocked down. It happens all the time in football games that smaller players will knock over larger players when they get better leverage, or are moving at greater speed.