▁the ▁ 1 0 0   m ▁and ▁trying ▁out ▁for ▁the ▁US ▁Olympic ▁Team ▁at ▁the ▁age ▁of ▁eigh teen . ▁He ▁joined ▁Florida ▁State ▁University ▁and ▁in ▁his ▁first ▁year ▁he ▁broke ▁the ▁ 1 0 0   m ▁American ▁junior ▁record ▁and ▁won ▁at ▁the ▁NCAA ▁Out door ▁Championships . ▁After ▁a ▁fourth - place ▁finish ▁at ▁the ▁ 2 0 0 5 ▁US ▁Championships , ▁D ix ▁continued ▁with ▁his ▁colleg iate ▁success , ▁setting ▁an ▁NCAA ▁record ▁of ▁ 1 9 . 6 9 ▁seconds ▁in ▁the ▁ 2 0 0   m ▁and ▁coming ▁within ▁one ▁hundred th ▁of ▁the ▁ 1 0 0   m ▁record . ▁He ▁completed ▁a ▁ 1 0 0   m , ▁ 2 0 0   m , ▁and ▁ 4 × 1 0 0 ▁meter ▁relay ▁swe ep ▁at ▁the ▁ 2 0 0 7 ▁NCAA ▁Out door ▁Championships , ▁the ▁first ▁to ▁do ▁so ▁since ▁John ▁Carlos ▁in ▁ 1 9 6 9 . ▁He ▁closed ▁his ▁amateur ▁career ▁in ▁ 2 0 0 8 : ▁another ▁NCAA ▁ 2 0 0   m ▁title ▁made ▁him ▁the ▁third ▁most ▁decor ated ▁track ▁ath lete ▁in ▁NCAA ▁history , ▁and ▁he ▁won ▁gold ▁and ▁silver ▁at ▁the ▁ 2 0 0 8 ▁US ▁Olympic ▁Tri als . ▁ ▁D ix ▁turned ▁professional ▁in ▁mid - 2 0 0 8 , ▁signing ▁a ▁mult im ill ion - d ollar ▁contract ▁with ▁N ike . ▁He ▁reached ▁the ▁Olympic