Ku qor sii wadida cutubkan - Dhacdadii ugu horreysay ee ciyaaraha naafada waxay ahayd markay jirtay 11 sano, iyadoo ku guuleysatay toddobo billadood oo dahab ah dhowr dhacdo. Sannadkii 2008, markay ahayd 14 jir, waxaa loo doortay inay u matasho Great Britain Ciyaaraha Paralympic-ka xagaaga ee Beijing, iyadoo ku dhammeysay kaalinta 11-aad ee haweenka F42-46 javelin. Waxay ahayd xubinta ugu da'da yar kooxda Great Britain ee 2008. Sannadkii xigay waxay ku guuleysatay billadoodii ugu horreeyay ee muhiimka ah markii ay ku tartantay 2009 IWAS World Junior Championships ee Switzerland, iyadoo ku guuleysatay qalinka F46 discus iyo naxaas ee F46 javelin. 2009 waxay ahayd sanadkii ugu dambeeyay ee Arnold uu ku tartamo horyaallada kubbadda, isagoo si buuxda diiradda u saaray waranka. Sannadkii xigay waxay horumar ku sameysay billaddeeda javelin markii ay lacag ku qaadatay 2010 IWAS World Junior Championship ka dibna waxay dahab ku qaadatay 2011 Championship oo lagu qabtay Dubai. Sanadkii 2011 ayaa Arnold uu u soo gudbay heerka sare isaga oo matalaya Britain tartanka horyaalka adduunka ee ciyaaraha fudud ee IPC
New Zealand; waxay ku dhameysatay kaalinta saddexaad ee F46 javelin, iyadoo qaadatay bilada naxaasta ah. Sanadkii 2012, waxay ku guuleysatay billaddii lacagta ahayd ee tartanka IPC. Sheekadeeda shaqsiga ah ee F46 javelin waxaa lagu diiwaan geliyay 35.88m bishii Juun 2012 ee tartanka Welsh Championships ee Cardiff, iyada oo ku jirta kaalinta labaad ee adduunka ee dhacdadeeda u socota Paralympics 2012. Rikoorka shaqsiga ah ee Arnold waxaa lagu kordhiyay Olombikada Paralympics ee 2012 ee London iyadoo lagu tuuray 36.27m. 22kii Luulyo 2013, Arnold wuxuu ku tartamay IPC Athletics World Championships ee Lyon. Waxay ku guuleysatay dahabka iyada oo ku guuleysatay 37.45m, iyada oo sii kordhinaysa rikoorkeeda shaqsiyeed.