Tennis
Players often use sweat bands on their wrists to keep their hands dry as well. Although the
game can be played in a variety of shoes, specialized tennis shoes have wide, flat soles for
stability and a built-up front structure to avoid excess wear.
Tennis is played on a rectangular, flat surface, usually grass, clay, a hardcourt of concrete
and/or asphalt and occasionally carpet (indoor).
In most professional play and some amateur competition, there is an officiating head
judge or chair umpire, who sits in a raised chair to one side of the court. The umpire has
absolute authority to make factual determinations. The umpire may be assisted by line judges,
who determine whether the ball has landed within the required part of the court and who also
call foot faults. There also may be a net judge who determines whether the ball has touched
the net during service. In some tournaments, certain line judges, usually those who would be
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