A study published in Sports Medicine found after surveying athletes at the 2011 International Association of Athletic Federations World Championships and Pan-Arab Games doping rates were much higher than rates previously suggested.
Here are five things to know:
1. After randomly surveying 2,167 athletes, results showed 30 percent of athletes at the International Association of Athletics Federations World Championships claimed to have taken doping drugs or used other doping methods.
2. At the Pan-Arab Games 45 percent of athletes reported to have taken doping drugs or using other doping methods.
3. During biological tests, only a fraction of these cases were detected:
• World Championships reported 0.5 percent of athletes took doping drugs
• Pan-Arab Games reported 3.6 percent of athletes took doping drugs
4. The study suggested that tests taken immediately before and during competitions find evidence of doping on average 1 to 3 percent. However, doping agents are often no longer detectable at this time if taken prior to competition.
5. Better results can be achieved through biological passports, which track athletes' medical data. This has shown an average of 14 percent of athletes use doping agents.