快猫短视频

SERVES are becoming so powerful in professional tennis, especially on fast
surfaces such as grass, that soon players will find it impossible to get to the
ball in time to return it. The technological fix? Bigger balls.

The International Tennis Federation, based in London, has enlisted engineers
to test the new balls, which are 6 per cent larger but with slightly thinner
skin than normal, so they still weigh the same. To test their performance, Paul
Rose of the ITF, along with mechanical engineer Steve Haake and his colleagues
from the University of Sheffield, used wind tunnel studies, racket impact tests,
and court simulations.

While the bigger balls bounced off the racket fractionally faster, they
slowed down in the air, and so took longer to reach the baseline. They also
bounced off the grass at a slightly steeper angle, giving players longer to
react. So for a serve of 190 kilometres per hour, the receiver had 16
milliseconds longer to reach the ball.

Sports technologists S茅an Mitchell and Mike Caine from Loughborough
University gave the balls to eight university players and found that rally
length increased from 4.5 shots to about 6, but the number of points per game
and games per match didn鈥檛 change, and neither did the outcome.

The players all preferred the larger balls, except for one, who relied on a
fast serve. Mitchell hopes players will adapt and rely on other strategies,
making the game more interesting. 鈥淲hat we want is variety,鈥� he says. 鈥淚f aces
are all you see, that can be dull.鈥�

The ITF began a test in January allowing use of the bigger balls in all forms
of tennis where they are optional. The ITF will decide whether to make them
compulsory.

But Geoffrey Bone of Britain鈥檚 Lawn Tennis Association, also in London,
is not convinced that slower serves would benefit top tournaments such as
Wimbledon. 鈥淭he serve-volley game is what Wimbledon is known for,鈥� he says. But,
says Andrew Coe of the ITF, if players continue to become better, taller and
stronger, 鈥渨e鈥檒l reach a threshold where serves are faster than human reaction
迟颈尘别蝉鈥�.