Claudia Pechstein is a German speed skater. She has won five Olympic gold medals. With a total of nine Olympic medals, five gold, two silver, and two bronze, she was previously the most successful Olympic speed skater, male or female, of all time,. Pechstein is the most successful German Winter Olympian of all time. After the World Championships in Norway in February 2009, Pechstein was accused of blood doping and banned from all competitions for two years.

Blood doping is a form of doping in which the number of red blood cells in the bloodstream is boosted in order to enhance athletic performance. Because such blood cells carry oxygen from the lungs to the muscles, a higher concentration in the blood can improve an athlete's aerobic capacity (VO2 max) and endurance. Blood doping can be achieved by making the body produce more red blood cells itself using drugs, giving blood transfusions either from another person or back to the same individual, or by using blood substitutes.