What are the characteristics of the four Grand Slams of tennis?

Representatives are Melbourne's Australian Open Center Stadium and Miami. 1988, Melbourne transformed the site surface into a hard ground, and covered it with a layer of rubber, commonly known as Rebound Ace. This kind of rubber floor has excellent elasticity, and the ball bounces high after landing. At the same time, because the surface elastic coefficient k is small, the interaction time between the ball and the ground is long, similar to the soft ground. The rubber surface is also mixed with plastic particles, which increases the surface friction coefficient μ. The combination of the above two factors makes the ball speed of rubber field relatively slow.

Because of the high bounce and slow speed, the bottom line style is slightly dominant. 1988-2003 The champion ratio of baseline play and online play was 1 1: 5, and the champion ratio of Agassi and Sampras was 4: 2. At the same time, it achieved a rare reversal in the classic World War I in 2000. These are closely related to the performance of the website. In this court game, there is still an advantage in serving, but it is not obvious. Playing topspin is more powerful, and some clay players may also play well on it, such as 1990 Must, 1997 Moya. The specific details are introduced in detail with 1995 Sana 'a final as an example.

It is worth mentioning that there are always netizens who say that the speed of the ball in the 1990 s was obviously slower than now, because the racket changed and so on. The change of racket technology brought revolutionary changes in 1985, which really improved the ball speed obviously. However, in the 1990s, the update of science and technology has been mainly reflected in amateur rackets, and the impact on professional players is not significant. However, the fans concluded that the slow speed of the ball in the 1990s was probably due to the misunderstanding caused by the two renovations of Melbourne Stadium.

1988, the stadium was changed from grass to plastic hard ground. A large-scale transformation was carried out in 2000. Although it is still a plastic surface, the ball is much faster. So, when you watch the Australian Open review program, you can see the Australian Open in the 1990s, which is a slow hard ground. Compared with the Australian Open in recent years, the speed is obviously much slower. But this is only the result of the change of the venue, which does not mean that the current ball speed is much faster than that in the 1990 s under the promotion of racket technology. If you look back at Wimbledon in the 1990s, you will find that the ball speed is faster than it is now, because the turf was longer then. The US Open has also undergone the transformation of the center court, and the reason is the same. The velocimeter in the 1990s was a laser, which measured the average of three points. Now it is a radar instrument that uses Doppler effect to measure the fastest speed of the hand, and the data compared with the speedometer can't explain the problem. Only one thing is certain. The wide application of modern forehand hitting makes forehand power more efficient. While gaining speed, the rotation is definitely stronger than before.

Concrete (concrete)

The representative is the Ashe Stadium of the US Open, which is the venue of the US Open series. This is commonly known as the cement yard. It's just that the cement field we play is bare, and there is a thin plastic covering or colored paint on it during the regular competition. The height and speed of the ball rebound are determined by the nature of the cover. This kind of court is the fastest among all the hard courts. Because the elastic coefficient k is large, the vertical component of kinetic energy is greatly lost, so the rebound of the ball is not too high (compared with the plastic court such as the Australian Open), and because the surface is smooth, the ball can obviously jump forward when it hits the ground (the plastic court and the ground obviously stop). Summer in North America is a happy time for internet surfers. On the fast hard ground, the service is very destructive, and it is obviously safer and more sure to intercept online here. 1990-02 season, online surfers took nine gold cups here, and Sampras maintained four victories against Agassi here. There will be detailed comments later.

However, it must be said that this kind of court is also the most uncomfortable court, and it is the main reason for players' lower limb injuries. Although it is more ornamental, we fans should not forget the players' feelings while enjoying the elegant Internet.

Grassland:

The representative is Wimbledon. This is a magical venue, an expensive venue, an elegant venue, a venue that is about to disappear. On the one hand, there are economic factors, on the other hand, fewer and fewer people are familiar with it.

Grass has the smallest friction and the lowest bounce (3/4 of hard ground). The ball slipped obviously after landing, which greatly reduced the time for players to prepare for hitting the ball. At first, the grass cover was uneven. With the progress of the competition, the grass roots and land are exposed where the ryegrass falls off, and the friction here will become more and more serious. In addition, the foundation is uneven. Therefore, the rebound of the ball on the grass is very irregular, which requires players to be familiar with the performance of the grass on the one hand and have good foresight and agility, on the other hand, they should try their best to use chopping and volleying. Cutting on the grass is more threatening than other sites, but it is not easy to intercept on the grass. Because the ball goes back and forth quickly, there is not enough time to surf the internet. Even before surfing the internet, in the face of returning the ball much faster than other venues, the adjustment of physical skills was very hasty, and the grasp of volley was not very high (compared with carpet). Even Rafter and Sampras often make incredible mistakes. However, the grass must surf the internet more. If you stay at the bottom line, it is more difficult to deal with bouncing balls.

The biggest advantage of grass is to infinitely amplify the power of serving. Here, it is also 180 km serving, and it is much more difficult to receive the service. The friction velocity loss of the ball passing through the grass is very small, and the rebound height is still low, leaving the receiver with little reaction space. Here, Ivan, Philip, Carat Esek and other heavy artillery have the opportunity to show their strength. The bottom line type is not that you don't play, but only those players who are moderate in stature, sensitive in response and far-sighted in receiving the serve can make full use of the power of the ball, make full use of their own style of play, and create cross opportunities with fast running to reach the peak. Agassi and Borg are both successful bottom line players. However, Agassi's two important defeats against Sampras and Becker also show that the owners of the grass are all players who serve the Internet without exception. Twenty-five years later, only Connors, Agassi and Hewitt won the championship.

Earth yard,

Broadly speaking, it includes real sandy soil sites, sites made of similar materials and synthetic sites. The correct name should be soft ground. Although the cost of construction and maintenance is quite expensive, the soft feet and the consequent protection of players have made this kind of venue popular again recently.

The earliest earth yard was built of sand. Low cost and comfortable land. Now it is also widely built in underdeveloped areas such as Latin America. But the drainage of natural land is a big problem.

At the beginning of this century, Europeans invented the quick-drying site, that is, spreading a layer of broken bricks or volcanic ash on the surface of the site, so that the water will seep down quickly and the surface will dry much faster. In relatively dry southern Europe, the thickness of the ground cover is relatively thin.

On the other side of the ocean, Americans invented the green soil field, that is, crushing the green stones naturally produced in the local area and laying them on the surface of the field, instead of using brick powder as in Europe. These two kinds of venues are now called ash yards. In areas with heavy rainfall or poor underground seepage conditions, drainage can be solved by building underground drainage systems; On the contrary, in arid areas, underground irrigation systems need to be built.

The third kind of "earth yard" is a plastic yard, which uses synthetic materials instead of natural materials to lay the surface of the yard. Although the cost is high, the maintenance cost is extremely low, so there is no need to consider the drainage problem. Moreover, the roughness of the ground can be achieved by increasing or decreasing rubber particles, and there are many choices of colors. The speed of this kind of stadium is not very fast, which is determined by the thickness and roughness of the surface layer. It is suitable for both surfing the internet and baseline.

Because of CCTV's "live broadcast", land is the most familiar and enthusiastic venue for China fans. I have translated an article about land before, so I won't talk about it any more. Just to add, there are great differences from place to place, such as Rome, Hamburg and Paris. It is difficult for the champion of Hamburg to win Paris, and there are many reasons for the venue. Also, sunlight has an impact on the hardness of each site, the most important being the soil field. 1996, Sampras beat Bruguera and Corell in a row (just like Federer beat kuerten and Ferrero in a row today), and the other two online players also reached the semi-finals, all thanks to God. However, the owner of the clay court is still a topspin master who follows Borg's style of playing. Occasionally, there are excellent kings in front of the net, and eventually they will fall under their pat.