Topspin

In ball sports, topspin or overspin is a property of a ball that rotates forwards as it is moving. Topspin on a ball propelled through the air imparts a downward force that causes the ball to drop, due to its interaction with the air (Magnus effect). Topspin is the opposite of backspin.

In baseball, the curveball, a type of pitch which usually has downward movement, is thrown in such a way as to put topspin on the ball. Its close relatives are the slider and the slurve. The "curve" of the ball varies from pitcher to pitcher.

In snooker, pocket billiards and billiards, players use topspin to keep the cue ball moving, including after it hits other balls. They get top spin by hitting the cue against the top of the ball.

In cricket, a top-spinner is a type of delivery bowled by a cricketer bowling either wrist spin or finger spin. In either case, the bowler imparts the ball with top spin by twisting it with his or her fingers prior to delivery. In both cases, the topspinner is the halfway house between the stock delivery and the wrong'un - in the wrist spinner's case his googly, and in the finger spinner's case his doosra.

A topspinning cricket ball behaves similarly to top spin shots in tennis or table tennis. The forward spinning motion impedes air travelling over the ball, but assists air travelling underneath. The difference in air pressure above and underneath the ball (described as the Magnus effect) acts as a downward force, meaning that the ball falls earlier and faster than normal.

In cricketing terms, this means that the ball drops shorter, falls faster and bounces higher than might otherwise be anticipated by the batsman. These properties are summed up in cricketing terms as a "looping" or "loopy" delivery. Also, the ball travels straight on, as compared to a wrist spin or finger spin stock delivery that breaks to the left or right on impact. A batsman may easily be deceived by the ball, particularly given that the action is quite similar to the stock delivery.

In delivery, the topspinner is gripped like a normal side spinner. For a legspinner the back of the hand faces the cover region and the palm of the hand faces the mid wicket region at release. For an offspiner, these directions are reversed. The ball is then released either with the seam going straight on to the batsman, or with a scrambled seam. A spinner will frequently bowl deliveries with both top spin and side spin. A ball presenting with roughly equal amounts of both is usually called an "overspinning" leg break or off break.

Tactically, a bowler will bowl topspinners to draw a batsman forward before using the dip and extra bounce to deceive them. In particular, batsmen looking to sweep or drive are vulnerable as the bounce can defeat them. In modern-day cricket Anil Kumble is considered the foremost leg spin exponent of the top spinner. Muttiah Muralitharan is an example of an offspinner who frequently uses this delivery.