Dear fellows since a long I have been puzzled by the cricket ball swing and reverse swing phenomenon. For fast bowlers when they(ball) throw ball(pitching with straight elbow vertically or near vertical movement of the arm) the ball swings may be towards the batsman(in swing) or away from the batsman(out swing). It is an Axiom among cricketers and cricket scientists world over that phenomenon is due to friction of air to one side of the ball(it is worth mentioning that most of the bowlers rub one side of the ball to keep the shine on it and keep the other side rough, that how the cheaters sometimes use bottle caps or others thing to rough one side).The older ball swing much more than the new. I am a medical doc but I have seen people swinging the soccer ball, ping pong ball and tennis ball and all the balls without keeping into the consideration the rough and smooth theory. I am, therefore, reluctant to accept this friction of air theory(may be it play slight part) but major element is how you throw the ball. All bowlers use two fingers on the seam or the ball(index and middle) and thumb on the other side of the .It is when one pushes the index or middle finger determines the swing of the ball(or some use angle of the arm during delivering the ball ). Is momentum of body play some role or in fact that is rough shine theory. Can some body please explain it?