Mezue ahịrịokwu na-esonụ: Vernon's debut na asọmpi egwuregwu mba ụwa bụ na
2004 IAAF World Cross Country Championships ebe ọ gbara asọmpi n'ọsọ ụmụ nwoke dị mita 8,000; na-emecha 64th na oge nke 27minutes na 12seconds. Asọmpi ọzọ nke Vernon bụ asọmpi mba ụwa nke 2005 IAAF World Cross Country ebe ọ gara asọmpi ọzọ na asọmpi ụmụ nwoke, oge a na-emecha 48th. Na 2005 European Athletics Junior Championships ọ gbara asọmpi na 5000meters; na-emecha nke anọ na oge nke 14minutes na 27seconds. N'ọnwa Disemba afọ 2005, ọ nwetara ihe nrite mba ụwa mbụ ya na European Junior Cross Country Championship na-emecha nke abụọ n'azụ Barnabás Bene nke Hungary. Mgbe ahụ, ọ gbara asọmpi na 2007 European Cross Country Championship wee kwụsị nke atọ na agbụrụ ụmụ nwoke na-erubeghị afọ 23. Na 2007 European Athletics U23 Championships Vernon gbara asọmpi na 5000meters wee kwụsị nke asaa na oge nke 13minutes na 59.24seconds. Vernon gbara asọmpi na 2008 World University Cross Country Championships, na-emecha nke isii. N'afọ 2008 bụkwa 2008 IAAF World Cross Country Championships ebe Vernon gbara onye nke 115 n'ọsọ 12kilomita nke ndị okenye. Asọmpi ya ọzọ bụ asọmpi European Cross Country nke 2008 ebe ọ gbara asọmpi n'asọmpi ụmụ nwoke n'okpuru afọ 23. Ọ gbara onye nke abụọ n'azụ onye Ịtali bụ Andrea Lalli. Vernon gbara asọmpi nke anọ ya na World Cross Country Championship na mbipụta 2009. Ọ gbara asọmpi n'ọsọ ụmụ nwoke ndị okenye wee kwụsị 78th. Na 2009 European Cross Country Championships na Dublin Vernon so na asọmpi ndị okenye nke ụmụ nwoke; na-emecha 12th.