Kammala jumla mai zuwa: Colman ya yi gasa a gasar zakarun duniya na IPC Athletics World Championships. A shekara ta 2002, ya lashe lambar tagulla a tseren tseren maza na mita 400 T53. A shekara ta 2006, ya lashe lambar tagulla a tseren maza na mita 800 T53. A cikin
A gasar zakarun duniya ta 2011, ya lashe lambar zinare a tseren tseren maza na 800m T53 da lambar azurfa a tseren maza na 400m T53. A Gasar Cin Kofin Duniya ta 2013 a Lyon, Faransa, ya lashe lambar tagulla a gasar maza na 800m da 1500m T53. An zaɓe shi don yin gasa a Gasar Zakarun Turai ta 2015 a Doha amma ya janye daga gasar.