ABSTRACT
Meaningful data on the prevalence of use of performance-enhancing drugs and methods in competitive sport are dif¿ cult to obtain. Evidence may be as diverse as statistics on positive dope tests, results of surveys of athletes about either their self-reported use or their perceptions of drug use by others, anecdotal reports, and investigative journalism (Yesalis et al . 2001 ). These sources of evidence are inconsistent (Dimeo and Taylor 2013 ). Speculation of levels of prevalence of drug use range from less than 1 per cent to more than 90 per cent. A number of studies have been undertaken to evaluate the prevalence of doping within individual countries or sports. However, it has been suggested that such studies generally underestimate the problem due to small sample populations (Lippi et al . 2008 ).
