Extensive training—and repeated drug tests—marked Kim Clijsters' preparation for her comeback.
Contesting her first WTA match in seven-and-a-half years, the 36-year-old Clijsters was impressive, but Garbiñe Muguruza was imposing on serve spoiling the Hall of Famer's return with a fierce 6-2, 7-6(6) triumph in the Dubai opener last Monday.
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Clijsters passed six out-of-competition doping tests in 2019 in preparation for her 2020 return to the pro tour, according to International Tennis Federation drug-testing records from 2019.
In comparison to Clijsters, fellow former world No. 1 Muguruza was tested 7 times in competition and 17 times out-of-competition, Simona Halep took 10 in competition and 17 out-of-competition doping tests, Maria Sharapova took 10 out-of-competition tests, Serena Williams was tested 6 times in competition and 5 times out-of-competition, Venus Williams was tested twice in competition and 14 times out-of-competition.
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