A gym where members will be encouraged to use marijuana to enhance their performance is due to open in San Francisco.

Power Plant Fitness – claimed to be the “world’s first cannabis-friendly gym” – is a joint venture between retired American football player Ricky Williams and Jim McAlpine, founder of the cannabis event series 420 Games, reports the International Business Times.

In the article, shared on the 420 Games blog, McAlpine told the IBT: “It won’t be a place to get high and just screw around. We are focused on the athletic side, not the cannabis side.”

Williams, who was suspended by the NFL after he tested positive for marijuana in 2004 and again for violating the NFL drugs policy in 2006, has spoken openly about how he believes marijuana can help NFL players. He returned to the game from 2007 until he retired in 2012.

Retired NFL player Ricky Williams Keith Srakocic/AP
Ricky Williams (Keith Srakocic/AP)

“I was a really good football player, a really good person, my teammates loved me, my coaches loved me, but my career and life were ruined because of a drug test,” he told IBT.

McAlpine added: “I think sports will become one of the bigger pieces of the marijuana industry. It’s very much in line with the idea that people and society are starting to understand that marijuana is medicine. Marijuana, if you use it in a responsible way, accentuates the parts of sports that you love and helps you to do them better.”

According to Tech Insider the gym will allow food containing cannabis to be consumed as well as vaping before it adds an outdoor smoking deck as smoking weed inside most public venues is currently banned in San Francisco.

“We will be helping our members figure out how is best for them to ingest their cannabis,” McAlpine told Tech Insider.

420 Games
420 Games (Olga Rodriguez/AP)

His other project – the 420 Games, which launched in San Francisco in 2014 and allows pot users and their families to take part in sporting events including a 4.20-mile run, aims to “reverse the lazy stereotypes about pot users”.

And Power Plant Fitness, which is due to open in the autumn, aims to do that too.

Scientifically, there is not much evidence to show marijuana improves sporting performance. However, University of Pennsylvania and John Hopkins University researchers are about to launch a scientific study of marijuana’s impact on NFL players, which is thought to be the first of its kind.