LOS ANGELES, USA (AFP) — NFL quarterback Peyton Manning hit back angrily yesterday at allegations in an Al-Jazeera documentary linking him to performance-enhancing drugs.

The five-time NFL Player of the Year, interviewed by ESPN at the Broncos’ facility in Denver, said he didn’t understand how the report was published when a key source had already recanted statements saying human growth hormone (HGH) had been shipped from an Indianapolis anti-aging clinic to the player’s household in 2011.

“I’m not sure I understand how someone can make something up about somebody, admit that he made it up, and yet somehow it’s published in a story,” Manning said. “I don’t understand that.

“It’s completely fabricated, complete trash, garbage. There’s more adjectives I’d like to be able to use. It really makes me sick.”

Asked if he had ever used HGH or any other performance-enhancing drugs, Manning said: “Absolutely not.”

The report titled The Dark Side was available on Al-Jazeera America’s website yesterday and set to air on television later in the day.

In it, British hurdler Liam Collins went undercover to expose the use of performance-enhancing drugs in sport.

As part of his probe Collins met with Charles Sly, described as a former pharmacist at the Guyer Institute in Indianapolis where Manning starred for the NFL’s Colts for 14 seasons.

Sly told Collins the clinic mailed HGH to Manning’s household in 2011, addressing it to Manning’s wife Ashley to avoid a link to the sports star.

However, in a follow-up with Al-Jazeera, Sly recanted his allegations, saying they were “absolutely false and incorrect”.

Sly has since told ESPN that he had no first-hand knowledge of what treatment Ashley or Peyton Manning may have received at the Guyer Institute.

“I feel badly,” Sly told ESPN. “I never saw any files. This is just amazing that it reached this point.”

The NFL collective bargaining agreement of 2011 banned the use of HGH. However, the league did not begin testing for the substance until 2014.

Manning missed the 2011 season because of multiple neck surgeries and joined the Broncos as a free agent prior to the 2012 campaign.

Manning, 39, said he was treated at the Guyer Institute, with the knowledge and supervision of Colts medical staff, using the clinic’s hyperbaric chamber and receiving other nutritional therapy as he sought to recover.

“I busted my butt to get healthy,” he said. “I put in a lot of hard work. I saw a lot of doctors… it steams me, whoever this guy is, insinuating I cut corners, I broke NFL rules in order to get healthy.”

Vancouver and Austin, Texas, were among the cities Collins visited for the documentary, posing as an athlete seeking performance-enhancing drugs.

He secretly recorded practitioners who provided him with drugs and coached him in their use.

Other US sports stars are named by Sly in the report, including former heavyweight world champion Mike Tyson and Major League Baseball players Ryan Howard and Ryan Zimmerman, although Sly has since told ESPN that he was “testing” Collins by dropping the names.

“Knowing Peyton Manning and everything he stands for, the Denver Broncos support him 100 per cent,” the team said in a statement yesterday.

Manning, who hasn’t played since November 15 because of a foot injury, said he realised that his denials would be greeted with scepticism by some.

“I can’t speak for any other athlete,” he said. “I know what I’ve done; how hard I’ve worked during my 18 years of playing in the NFL.