Jamaican 400 metres runner Dominique Blake has had her drug ban reduced from six to four-and-a-half years by the Court of Arbitration for Sport.

CAS ruled that the suspension handed down to Blake by the Jamaica Anti-Doping Appeals Tribunal for testing positive for banned stimulant methylhexaneamine at the Jamaican Olympic trials ahead of London 2012 was "too severe".

It was the 27-year-old's second doping offence after she had previously served a nine-month suspension.

CAS said in a statement there had been "some mitigating factors", but added Blake had "failed to establish that she bears no significant fault or negligence" for the positive test.

The period of ineligibility is back-dated to July 1, 2012, meaning she will be able to return at the start of 2017.