Here is a riddle: How is tennis pro Maria Sharapova like a Cold War Soviet super-soldier? The answer is that both took the cardiac drug meldonium.

The difference, though, is that the 69-year-old Latvian chemist who invented the drug says only the super-soldiers were his intended use case. Ivar Kalvins, chair of the scientific board of the Latvian Institute of Organic Synthesis (which, yes, sounds like the name of a place you’re trying to clear in a first-person shooter, but OK) says he started working on the drug in people for use by Soviet troops in Afghanistan. “If the soldiers are to operate in the mountains, there’s a lack of oxygen,” Kalvins says. “The way to protect against damage is by using Mildronate.”

And indeed, Mildronate—that’s the brand name for meldonium—gave struggling recruits super-powers. Users had extra endurance and oxygen-carrying capacity that let them carry heavy backpacks over high-altitude mountain ranges and desert plateaus during the Soviet Union’s invasion of the rugged nation from 1979 to 1989. In fact, Kalvins was a finalist for the European Inventor Award in 2015 (from the European Patent Office) for his work on the drug.

During the Soviet era, according to Kalvins, the Latvian firm Grendiks shipped hundreds of metric tons of Mildronate to the Russian army. “There were very many who used it,” he says.

All well and good, but in January the World Anti-Doping Agency said athletes shouldn’t be among them. The agency banned it in light of a 2015 study that found 2.2 percent of athletes tested positive for the stuff.

Kalvins says the ban is literally a crime. “It’s a violation of human rights,” he says. “The sportsmen should be able to protect their health. We are living in an era of evidence-based medicine, so there are not any other new data supporting the ban.” He calls the prohibition “sudden” and “a surprise.”

So was Sharapova trying to get super-powered endurance or treat a heart condition, as she claimed on Monday? It’s true that athletes from Russia and the former Soviet countries are having a particularly hard time obeying WADA’s rules on drug use, and that meldonium seems especially popular with athletes from that region. Also, Grendiks says the appropriate course of treatment for a heart condition is four to six weeks, not the 10 years that Sharapova says she used it.

Grindeks spokeswoman Ilze Gailite says Mildronate is a safe, effective drug used to combat various heart conditions and diabetes. “There have been no clinical studies providing scientific evidence that acute or chronic use of meldonium increases the athlete's physical ability. Any suggestions to include meldonium in the prohibited list have no scientific basis and are not justified,” Gailite writes in an email. “We strongly believe that meldonium should not be considered as doping but an effective medicine which is widely used in clinical practice and it should not be included in the Prohibited list.”

WADA disagrees, obviously. Nobody there would comment, but in a statement Tuesday the agency said it banned meldonium "because of evidence of its use by athletes with the intention of enhancing performance.” In other words, if you use it to enhance performance, it’s a performance enhancer, and that’s a big nyet-nyet.

Here’s another riddle: How are Maria Sharapova and Soviet super-soldiers like Russian speed skaters? Take a guess. Three of those champion skaters have tested positive for meldonium use. The Associated Press reported Wednesday from Moscow that Russian ice skating officials said the champs are innocent, the victims of “sabotage” by jealous teammates who spiked their urine samples. The speed-skating association has hired British lawyers to argue their case.