Isku day inaad ku guulaysato ciyaaraha Olombikada xagaaga ee 2004 ee Athens, Alleyne wuxuu sii waday barnaamijkiisa isagoo u qalma laba tartan oo dabaasha ah. Wuxuu ka saxiixay FINA B-ta caadiga ah ee 51.89 (100 m freestyle) iyo 1:53.19 (200 m freestyle) ee Ciyaaraha Pan American ee Santo Domingo, Dominican Republic. 200 m oo qaab xor ah, Alleyne waxay la tartantay toddobo dabaasha kale oo ku jiray heerkulka saddexaad, oo ay ku jiraan laba jeer oo kale oo Olombikada ah Joshua Ilika Brenner oo reer Mexico ah iyo Giancarlo Zolezzi oo reer Chile ah. Wuxuu ka adkaaday Mahrez Mebarek oo reer Algeria ah si uu u helo kaalinta saddexaad iyo soddon iyo afaraad guud ahaan 0.11 ilbiriqsi 1:52.89. Tartankiisii labaad, 100m oo qaab xor ah
, Alleyne ayaa kaalinta 48aad ka gashay tartankii hore ee subaxnimadii. Dabaasha heerkulka saddexaad, Alleyne wuxuu la jaanqaaday waqtigiisii gelitaanka ee 51.89 si uu u badbaadiyo booska shanaad ee ka sarreeya Max Schnettler oo ka tirsan Zolezzi oo ah 0.02 ilbiriqsi.