Maria Sharapova has announced her retirement from tennis at the age of 32 years old. The Russian starburst on to the scene in 2004 when she stunned the sporting world by winning Wimbledon at 17. She went on to win a total of five Grand Slam titles but her career never recovered after serving a two-year drugs ban for testing positive for meldonium. Injuries to her shoulder and arm over the past 18 months led her to decide to hang up her racket after returning to Los Angeles from the Australian Open...