Post-tensioned concrete is reinforced with a grid of high-strength sheathed steel tendons, or cables. While the concrete is curing, the cables are tensioned in both directions and held permanently under stress by anchoring them in a perimeter beam. This squeezing action keeps the concrete in compression, improving its tensile (or bending) strength. The more the concrete is squeezed together, the less likely it is that shrinkage cracks will develop or open. (See a more complete description of post-tensioning from the Post-Tensioning Institute.)
This is a great question because it is so important to playing the game well. A grip size that is too small will cause your hand to slip on your racquet a little and a grip size that is too big will restrict your wrist movement and make it hard to adjust your grip as you play.To measure your grip you need to take out a measuring tape. Place your fingers on your hand extended out and together and then turn your palm up. With the measuring tape take a measurement from the very end of your ring finger down to the bottom crease in your palm (usually adjacent to where your thumb attaches to your palm). That will be the size grip you need to look for. It usually will fall between 4 inches and 4 ¾ inches on most people.Keep in mind that you may want to add a layer of grip tape to your new racquet like many people do. If you are one of those people then it is best to get a grip size that is one size smaller than what you measured your hand to be. This will allow for the extra grip tape without making the grip too big for your hand.
In standard play, scoring beyond a "deuce" score, in which both players have scored three points each, requires that one player must get two points ahead in order to win the game. This type of tennis scoring is known as "advantage scoring" (or "ads"). The side which wins the next point after deuce is said to have the advantage. If they lose the next point, the score is again deuce, since the score is tied. If the side with the advantage wins the next point, that side has won the game, since they have a lead of two points. When the server is the player with the advantage, the score may be called as "advantage in". When the server's opponent has the advantage, the score may be called as "advantage out". These phrases are sometimes shortened to "ad in" or "van in" (or "my ad") and "ad out" (or "your ad"). Alternatively, the players' names are used: in professional tournaments the umpire announces the score in this format (e.g. "advantage Nadal" or "advantage Williams").
The rules of modern tennis have changed little since the 1890s. Two exceptions are that from 1908 to 1961 the server had to keep one foot on the ground at all times, and the adoption of the tiebreak in the 1970s. A recent addition to professional tennis has been the adoption of electronic review technology coupled with a point-challenge system, which allows a player to contest the line call of a point, a system known as Hawk-Eye.