The World Anti-Doping Agency (WADA) Monday described allegations made in an Al-Jazeera report that Denver Broncos quarterback Peyton Manning took human growth hormone (HGH) as "very concerning" and has urged "increased collaboration" with sports leagues in the United States. Though Manning has vehemently denied the allegations and the source of the Al-Jazeera report has since recanted the claims he was shown making in the film, WADA says that it expects a careful investigation by the relevant authorities. The Dec. 27 investigative documentary ‘The dark side: The secret world of sports doping,' linked well known players from the National Football League (NFL) and Major League Baseball (MLB) with performance enhancing drugs. "Al-Jazeera's allegations are very concerning, particularly as it relates to the NFL's and MLB's testing programs," David Howman, director general of WADA, said in a statement. "While the NFL and the MLB are not signatories to the World Anti-Doping Code, in recent years WADA has been working with them and other professional leagues in the United States to try to bring them closer to WADA's program. "In particular with the NFL, we have been offering guidance to enhance, and increase the transparency of, their testing program. "We would of course welcome increased collaboration with the leagues and their players' associations to discuss appropriate enhancements that could be made in support of clean athletes." The Al-Jazeera report claimed that Manning took human growth hormone following neck surgery in 2011, and Sunday the football player acknowledged he visited a clinic that allegedly supplied the banned substance. However, Manning, who missed the entire 2011 National Football League season with a serious neck injury, strenuously denied the claim made by the news network's report that he had used human growth hormone.
