Contador reiterates threat to quit if punished in clenbuterol case

Alberto Contador made an emotional plea of innocence during his press conference

Alberto Contador made an emotional plea of innocence during his press conference (Image credit: AFP)

Triple Tour de France champion Alberto Contador made a rare public appearance on Thursday, repeating his threat to walk away from professional cycling if he is found guilty and sanctioned over a positive Clenbuterol test from the Tour de France this year.