On Manning controversy, expert says, 'it wouldn't make sense' to use HGH in recovery

Christopher Mendias saw the Al Jazeera report on Peyton Manning's alleged tie to human-growth hormone over the weekend, and one question immediately sprung to mind:

"Why would he use HGH for that?"

Mendias' opinion matters. He has been studying growth hormone for a decade at the University of Michigan, where he's an assistant professor of orthopedic surgery. He is also leading a project funded by Dallas Mavericks owner Mark Cuban to learn how HGH can help recovery from ACL tears.

Manning's injury was far from an ACL injury; it was a herniated disc affecting the nerve in his neck. And that made Mendias curious when he saw the report.

"Even if he did use it," Mendias says, "it wouldn't make sense for the injury he had. For having a bulging disc, I don't think he'd benefit."

The injury made Manning too weak to throw a football with his usual velocity, so it would seem that any added strength would help him recover. But Mendias says the muscles around the impacted nerves would restore themselves soon after the nerve did – without anything performance-enhancing.

"It's the nerve causing the weakness," he says. "Not the muscle itself."

Manning has adamantly denied using any performance-enhancing drugs, going as far as to threaten a defamation lawsuit against Al Jazeera.

Part of the problem with the discussion of PEDs is the lack of awareness (and proof) of what they actually do. Many sports fans believe HGH is a super serum, able to create a stunning metamorphosis of the body.

There's not a lot of evidence for that.

In 2008, a study of growth hormone's effects on athletic performance was published in the "Annals of Internal Medicine." The results were hardly a ringing endorsement.

"Growth hormone is reported to be extensively used for illicit enhancement of athletic performance, both for its anabolic and endurance effects," wrote the authors. "However, our review of the limited published literature suggests that although growth hormone may alter body composition, it has minimal effect on key athletic performance outcomes and may, in fact, be associated with worsened exercise capacity."

In other words, maybe HGH will help you look shredded, and perhaps it can assist with recovery, but it won't necessarily help you improve in your sport.

More recently, a 2014 study from the University of Western Sydney published in the Journal of Internal Medicine reported, "Sprint capacity was increased significantly with [growth hormone] administration in the group of men and women combined by 3.9 percent." But 3.9 percent is relatively close to the margin of error for most studies, and even allowing for that possible benefit, Manning wasn't trying to get faster.

This doesn't mean HGH is useless; it just adds doubt to the premise that it makes an enormous difference for pro athletes. And in Manning's case, even if he obtained it and used it – a claim that the Al Jazeera report doesn't make – it's hard to argue it helped him heal from his neck injury.

Mendias' project goal is to assist athletes not only in recovery, but also in warding off long-term damage. The study is ongoing, and Mendias says he doesn't know what the results will be, but here too is another distinction between knee injuries and what Manning faced: the ACL is a ligament, and Manning had issues with pinched nerves.

It's not even clear that Manning's visits to the Guyer Institute helped; Mendias says a lot of the treatments athletes use for recovery might be restorative only as a placebo effect. The athlete thinks it's helping, and so physiologically, it does just that.

In some ways, the mind is the best performance-enhancer of all.