But his continued strong performances have provoked speculation and criticism , much to his frustration .
Gatlin has been twice suspended for illegal substances , including a four - year suspension that ran from 2006 to 2010 .
Gatlin 's continued strong performances have provoked speculation and criticism , much to his frustration .
Gatlin has been twice suspended for illegal substances , including a four - year suspension that ran from 2006 to 2010 .