Jannik Sinner reappoints trainer he sacked after positive doping test Sport Wimbledon champion Jannik Sinner has reappointed his former fitness trainer, who he sacked following his positive doping tests last year. Sinner parted ways with his fitness coach Umberto Ferrara and physio Giacomo Naldi last summer, after it was announced that the Italian tennis superstar had twice tested positive for the steroid clostebol in March 2024. [...]