Photo Gallery The Problem of Doping
Blood doping has long been prevalent in professional cycling and has particularly plagued the Tour de France. Here, Spanish rider Manuel Beltran riding at the Tour de France in 2007. He became the first rider -- among many -- to test positive for doping that year.
The US sprinter Justin Gatlin became one of the highest-profile cases in recent years after he was tested positive after setting a 100-meter world record in 2006. He was banned for four years.
Former German cycling professional Jan Ullrich has long been dogged by suspicions of doping. Many from Team Telekom, for whom he used to race, have admitted to doping and have indicated that Ullrich too may have taken part. Ullrich, though, has long denied the charges.
Providing blood and urine samples to anti-doping officials has become part of being a professional athletes. Random tests are carried out at all major international sporting events. But doping methods continue to get more and more sophisticated.
Due to a string of doping admissions and the ongoing prevalence of doping in professional cycling, Deutsche Telekom withdrew from cycling sponsorship in November 2007.
The Tour de France was hit particularly hard in 2006 when Floyd Landis, who won the race that year, was tested positive for doping and stripped of his title. Landis has denied the charges.
US sprinter Marion Jones was stripped of five Olympic medals she own in 2000 in Sydney after admitting that she took performance-enhancing drugs.
Investigators are worried that many designer drugs and doping techniques are undetectable. So-called "genetic doping" may present a new problem in the not-too-distant future.
This year's Olympic Games in Beijing was also overshadowed by doping. However, suspicion that Usnain Bolt of Jamaica (shoes seen here) used performance enhancing drugs to break world records in the 100 and 200 meter races were not substantiated.
