Topspin

In ball sports, topspin 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. Topspin is the opposite of backspin.

In tennis, because of a net being in the middle of the court, using topspin will increase the player's consistency. Topspin also allows a player a greater margin of error. Because topspin brings the ball down toward the ground quicker, a player can hit the ball higher over the net, thus increasing the margin of error. This may help in lobbing an opponent who is waiting at the net, or playing directly to a player's feet. Hitting low to high as the player approaches the contact point will impart lift. Keeping the racquet face (the strings) slightly closed from perpendicular will impart the topspin to the ball that the player wants. However, balls that bounce lower due to greater force or backspin are much more difficult to return using a grip that confers topspin such as the semi-western and western grips, as the racket is angled too far downwards to 'lift' the ball back over the net. As such, topspin is more effectively used on slower, higher bouncing surfaces such as clay. Topspin is also far more difficult to impart on backhand strokes due to the physical limitations of an arm stretched across the body.

Physical explanation

Topspin on a shot imparts a downward force that causes the ball to drop, due to its interaction with the air. In racquet sports, it can be generated by hitting the ball with an up-and-forward swing, with the racquet facing below the direction it is moving. A topspin shot is the opposite of the slice; topspin itself is the opposite of backspin.

One way of explaining the Magnus effect is that - because of the rotation and the fact that air acts as a viscous or "sticky" substance on the surface of the ball, a stream of air in the wake of the ball is being ejected upwards. As a reaction to this, the ball is pushed downwards.

Often Bernoulli's principle is used to explain the topspin effect, as the difference in speed between ball surface and air is greater on the top of the ball. For example, if the air flowing past the bottom of the ball is moving faster than the air flowing past the top then Bernoulli's principle implies that the pressure on the surfaces of the ball will be lower below than above. In other words, since there is more air friction occurring on the top surface of the ball compared to the bottom, this differential causes a greater pressure to be applied on the top of the ball, resulting in the ball being pushed down.

Competitive utility

The topspin shot is very effective on hard surfaces. The ball spins forward and descends toward the ground quicker, so it can be hit with more force compared to another type of shot.

On most court surfaces, topspin also makes the ball bounce higher. As a result, it is often used on clay or "soft" court surfaces which have a naturally higher bounce, in order to make the ball harder for the opponent to hit. An opponent with a one-handed backhand is especially vulnerable to a topspin shot because it is difficult to hit a high ball with a one-handed backhand.

• Outline
  

  SPORTS WORLD

  Tennis

  Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball covered with felt over or around a net and into the opponent's court. The object of the game is to play the ball in such a way that the opponent is not able to play a valid return. The player who is unable to return the ball will not gain a point, while the opposite player will.

  History: Historians believe that the game's ancient origin lay in 12th century northern France, where a ball was struck with the palm of the hand.

  Equipment: Part of the appeal of tennis stems from the simplicity of equipment required for play. Beginners need only a racket and balls.

  Court: A tennis court is the venue where the sport of tennis is played. It is a firm rectangular surface with a low net stretched across the center.

  Manner of Play: The players (or teams) start on opposite sides of the net. One player is designated the server, and the opposing player is the receiver.

  Point: A point in tennis is the smallest subdivision of the match, the completion of which changes the score.

  Official: In tennis, an official is a person who ensures that a match or tournament is conducted according to the International Tennis Federation Rules of Tennis and other competition regulations.

  Shots: A competent tennis player has eight basic shots in his or her repertoire: the serve, forehand, backhand, volley, half-volley, overhead smash, drop shot, and lob.

  Grips of Racket: A grip is a way of holding the racquet in order to hit shots during a match. Most players change grips during a match depending on what shot they are hitting.

  Strategy: Players use different tennis strategies to enhance their own strengths and exploit their opponent's weaknesses in order to gain the advantage and win more points.

RESOURCES
This article uses material from the Wikipedia articles "Tennis" and "Topspin", which is released under the Creative Commons Attribution-Share-Alike License 3.0.