Tulis hiji continuation for this paragraph - As of 2013, kinerja pangalusna Seifert di Dunya Championships sumping dina 2011, nalika anjeunna meunang medali pérak salaku anggota tim Jerman 5000m relay. Kinerja individu pangalusna na di hiji Championship Dunya éta dina 2012
, nalika anjeunna sumping ka 4 dina 500 méter. Manéhna ogé meunang medali pérak salaku anggota tim relay Jerman di 2010 European Championships.