Professional athletes have started to push the boundaries when it comes to gaining an edge or prolonging their careers. Cryotherapy, in which users submerge their bodies in freezing temperatures for a short amount of time, has now become a mainstream form of treatment for countless pros.

So what’s the next fad that sport stars are doing that might become a regular thing?

Here are five outlandish treatment options that some athletes swear by:

Viagra

‘Viagra-like’ drug maker says 140 million Chinese men are impotent – shares rise sharply

According to an article in the UK’s Daily Mirror, football players from San Lorenzo, an Argentinian league club, used Viagra to prepare for a match at high altitude. The team used it while playing against Bolivian side Bolivar at Estadio Hernando Siles stadium, which sits at 11,932 feet above sea level.

The idea is that Viagra promotes blood flow to all areas of the body, not just a man’s genitals. Thus more blood flowing to the lungs could help with oxygen intake where oxygen is more scarce.

Of course, no athletes have come out publicly stating they use Viagra to help them perform, outside the bedroom, however the science of both the pill and athletes suffering greatly in high altitude settings are medically proven.

NFL player Brandon Marshall, who is a free agent, said many of his teammates used it to gain an “edge” during games. And given the drug is not banned and readily available via a doctor’s prescription, it flies under the radar when it comes to banned substances as well.

Cupping

Five things you should know about cupping, Chinese medicine therapy on view in Rio

This one looks to be breaking into the mainstream lately, as even some celebrities have been spotted sporting red circular bruises all over their bodies. The procedure, which is seen as another form of acupuncture, features a flammable liquid and a vacuum-like sucking cup to promote blood flow, stimulate muscle flow and reduce inflammation.

While it is an ancient treatment, the science is still undecided on whether there are any tangible medical benefits. A recent Harvard Health Blog post said it is tough to study via blinded placebo-controlled trials given the procedure can be painful. With skin discolouration and soreness the only noted downfall, its non-invasive style is also appealing to many athletes.

Michael Phelps is probably one of the most famous regular users as his Instagram is littered with photos of him sporting the post-treatment marks. He even competes at swimming meets covered in cupping marks.

Regenokine Therapy

View this post on Instagram

In case u were wondering.. #germany #fyi

A post shared by Kobe Bryant (@kobebryant) on Oct 7, 2013 at 8:45pm PDT

Kobe Bryant gets Fiba Basketball World Cup 2019 ambassador role in China with Yao Ming

This controversial treatment involves extracting blood from a patient and heating it before the blood is put in a centrifugal and spun to separate it into its constituent parts. This forces a layer of red blood cells to the bottom of the tube, which acts as a serum. Finally, the blood is injected back into the patient, usually in an area where an injury has been sustained.

The idea is that the red blood cells can speed up recovery time as well as bring immediate pain relief to an effected area.

While it sounds a bit far fetched, many professional athletes swear by it. A SBNation article from 2017 noted six NFL Seattle Seahawks players were getting the treatment in hopes of allowing them to be ready to play by opening day. Also, Kobe Bryant uses it on his knees, which he has had surgically repaired.

Hyperbaric Oxygen Therapy

Hong Kong Hospital Authority mulls high-pressure oxygen therapy

According to scientific data, the air we breathe on a regular basis contains only around 21 per cent oxygen. Hyperbaric oxygen therapy (HOT) ramps that up to 100 per cent in a small pressurised environment. Athletes spend anywhere from 30 minutes to one hour inside a small tube, and pass the time by watching TV or reading.

The claim is that the increased oxygen supports the production of new blood vessels (once again red being the key colour), which in turn can help injuries heal faster. A recent medical study out of the US also found that HOT can induce something called angiogenesis, which helps with the regeneration of nerve fibres in people who have suffered a traumatic brain injury. It was also shown to help neuroplasticity, which is one of the main ways the brain repairs itself.

The list of athletes who use HOT is long: Cristiano Ronaldo, Novak Djokovic, former NFL star Terrell Owens, NHL player Paul Kariya and NBA great LeBron James all use it on a regular basis.

GyroStim

Frightening link: suicide risk triples for concussion patients, study finds

When it comes to strange, the GyroStim takes the cake. This multi-axis chair that rotates can apparently help with brain function. Patients get into the device, spin around and it is supposed to help improve balance by forcing the brain to adapt to unfamiliar and odd positions.

The weird procedure has been called science “quackery”, but some athletes have said it has helped them recover from post concussion symptoms.

One again, outside nausea and dizziness, the procedure is fairly non-invasive, meaning if you can derive some type of benefit from it, placebo or not, and can afford the hefty price tag, it comes with a decent cost-benefit analysis argument.

According to GyroStim’s website, the procedure challenges your “vestibular system”, which can in turn reduce a sensitivity to motion.