The international court of arbitration for sport or CAS has upheld the two-year ban of German speedskater Claudia Pechstein for a doping rule violation. +++ LM REIN +++ 37-year-old Pechstein, a five-time olympic champion, had appealed against the ban, which skating's governing body the ISU imposed in July. Pechstein did not actually fail a doping test, but showed abnormally high levels of immature red blood cells.