Since he's been in Washington for the Legg Mason Tennis Classic, Michael Chang has had 27 rackets strung. But Chang is particular. He cannot have just anyone string his rackets, which must be done shortly before his matches begin. After trying out a few different candidates, Chang chose Bryan Cohen of Rockville to become his personal stringer. Cohen, 27, attended Wootton High School and has been stringing rackets for about half of his life.

Cohen was hired by Chang after Legg Mason last year and never imagined he would travel the world. During matches all over the world, Cohen usually sits somewhere so he can see Chang and his coach, brother Carl Chang. Often, Cohen will be given a signal by Carl to string up another racket with either higher or lower tension, depending on what Michael wants.

In a match, Chang rotates between several rackets and generally ends up using four or five rackets. When Chang reached the semifinals of the U.S. Open last year, he had 92 rackets strung by Cohen. "If the strings get soft, the balls will tend to fly and Michael will lose some control," Cohen said.

On the road, Cohen carries several duffel bags, including a 120-pound case — 2½ feet high, 4 feet wide — that contains his stringing machine. Several hours before Chang was scheduled to play Jim Courier last night, Cohen was busy stringing rackets. "If they sit around too long, they'll lose tension," Cohen said, explaining why he didn't string the rackets much earlier. "He likes me to string up some fresh ones."

Cohen could not be more pleased about working for Michael and Carl. "They're quiet in general," Cohen said. "They're a very close-knit family, and they've been extremely nice to me. They are very appreciative of what I do."

Chang, Andre Agassi, Pete Sampras and Boris Becker of Germany are the only players who have personal stringers, according to Cohen.

Bryans Are Double Trouble
Twin brothers Mike and Bob Bryan overcame an early deficit to advance into the semifinals of the doubles draw, defeating David DiLucia and Michael Sell, 4-6, 6-3, 6-2. Relying on strong service games and quick reflexes at the net, the Bryans continue to roll in their professional debut in an ATP Tour event.

"This is the best tournament we've had in our lives," Mike said. "To be pros for three weeks and already be in an ATP Tour semifinal is amazing."

Immediately after the match, Wayne Bryan, the father of the twins, went to a phone and called his wife, Kathy, in Camarillo, Calif. She had been waiting by the phone for hours and began to cry.

The Bryans remain undefeated in 17 professional matches, and have not lost a match since losing in April to the team they will face in the semifinals: South Africans Grant Stafford and Kevin Ullyett.

While collegiate players at Stanford, the Bryans were beaten by Stafford and Ullyett in the quarterfinals of a professional event in Atlanta, 6-3, 6-3.