After sweeping the 2008 Summer Olympics in Beijing, where he earned eight gold medals, American swimmer Michael Phelps was caught bong-handed in a photo that quickly spread across the internet. Confronted with widespread censure and speculation about future disqualification, Phelps was forced to make the media rounds, apologizing for smoking marijuana after breaking his own record in an outstanding Olympic performance.

But for many, the candid photo raised another kind of question: Could pot be used as a performance enhancer? In the end, the athlete's bong mishap has become a symbolic example of marijuana users defying stereotypes of laziness. Indeed, the more we learn, the more we come to realize that these stereotypes are rooted in misconceptions about how marijuana affects the human body and mind. And in several recent studies, researchers took on the question that Phelps' celebratory bong rip raised, finding that cannabis does, in fact, have a positive impact on exercise.

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For one, using marijuana has been shown to have an anti-inflammatory effect. Injuries from workouts can cause muscle tissue to swell and feel sore, and smoking pot can reduce that inflammation, allowing you to go the extra mile without using drugs that erode the stomach lining. A 2009 study, published in the journal Future Medicinal Chemistry, described marijuana as a "potent anti-inflammatory agent" that had "significant potential" to be used for the treatment of inflammatory and autoimmune disorders.

Related: What does marijuana do to your lungs, bones, cancer cells, breast cancer, metabolism, sex drive, and sleep?

Even the World Anti-Doping Association banned cannabis, as Outside Magazine reported, citing research about the effect of marijuana on anxiety and lung functioning. Because the substance has been shown to reduce anxiety and increase airflow to the lungs, the organization concluded that pot is, essentially, a performance enhancer that could give users an advantage over non-users. As it happens, this is actually a fair point. Not only does it provide these health benefits, but marijuana also improves the overall endurance of athletes.

Running while high versus running while sober.

Compelled by anecdotal evidence about the influence of marijuana on athletic performance, Outside correspondent Gordy Megroz conducted his own experiment, overseen by Dr. Stacy Sims, a physiologist who studies the science of sports. She recommended that Megroz take a battery of tests and compare the results of various workouts he did both sober and high.

While he was sober, he made it 19 minutes on the treadmill, starting at five miles per hour and increasing the ramp angle by 2.5 percent every two minutes. Then he took a hit and jumped back on the exercise machine, finding that the experience was "much different."

"I can still feel the pain, but I’m not fixated on it; my mind is lost in random thoughts," Megroz wrote. "Finally, my legs stop turning over quickly enough and I hit the stop button: 19:30." He repeats the test two more times over three days, and the results are consistent. Sims confirms that this is a "substantial performance gain."

"My experience is less surprising when you examine the science. When we run, our bodies actually produce endocannabinoids, a naturally occurring form of THC which, along with endorphins, are responsible for the runner’s high that athletes enjoy. Smoking pot simply puts you in that state before your body begins generating the chemical."

To be sure, the relationship between pot and pain has been strongly established. It is one of the least controversial findings that research has proven in the past thirty years. Marijuana significantly reduces pain. Coupled with its anti-inflammatory properties and the fact that using marijuana has been shown to improve lung functioning, however, and suddenly you begin to understand just how effective pot can be in the gym, on the field, or in the pool. And that's also why it makes sense that the World Anti-Doping Association banned pot. It really does seem to be a performance enhancer.

So why is marijuana illegal? Check out our video explaining the history of the drug in the U.S.: