 Kọ itẹsiwaju fun paragirafi yii - Ni 2010 World Junior Championships in Athletics ni Moncton, Canada, Mance gba ami ẹyẹ goolu lori 4 × 400 mita relay. Ọdun kan sẹyin, ni 2009 World Youth Championships in Athletics ni Brixen, Italy, o gba ami-ẹyẹ fadaka lori awọn mita 400, ti o pari keji si Olimpiiki ti ọjọ iwaju. : àti ògbóǹkangí òṣèré Kirani James. Ní oṣù kẹfà ọdún 2010, ó ṣe ìbúra fún USC Trojans. 