Outswinger

An outswinger is a type of delivery in the sport of cricket. It is bowled by swing bowlers.

An outswinger is bowled by holding the cricket ball with the seam at an angle and the first two fingers running along either side of the seam. Once the ball has worn and been polished so that one side is rougher than the other, the rough side is placed on the left (as seen from the bowler's viewpoint). When the bowler delivers the ball, he angles the seam so that it points slightly to the left as well, and releases the ball rotating about a vertical axis with the seam along the rotational axis. The angle of the seam to the direction of motion produces an aerofoil effect as the ball moves through the air, pushing it to the left. This is enhanced by differential air pressure caused by movement of air over the rough and smooth surfaces, which also tends to push the ball to the left. The result is that the ball curves, or swings to the left.