There are many factors that affect the flight of the golf ball. Perhaps the most influential is the angle of attack that the club comes into the ball. Generally the steeper the angle of attack the greater the amount of backspin imparted on the ball. A golf ball that is struck in such a way with a short iron will tend to have a very distinctive trajectory and will come down almost vertically and will often spin backwards (depending on how well it was struck, the green, and the type of ball).