Sheremetiev said: “It’s a good drug. Until they banned it, we used it in many types of sport: hockey, skiing — in those where there’s pretty serious strain.”

Grindeks said in a statement that it did not believe meldonium should be banned for use by athletes because it “cannot improve athletic performance but it can stop tissue damage in the case of ischemia,” which is the lack of blood flow to the heart.

Until the ban, Sheremetiev said, he had given the drug to his own athletes about twice a year.

Sharapova and her lawyers said she was prescribed meldonium by her family doctor in 2006 for a variety of health problems, including signs of diabetes, irregular EKG readings, magnesium deficiency and frequent cases of the flu. She said she had failed to read an email sent by WADA that confirmed the medication had been added to the prohibited list for 2016.

The Russian trainers and officials said they were obeying the ban on meldonium, but they insisted the drug — despite its benefits — should not be considered a performance enhancer. Sheremetiev and other team physicians said it was merely for restoring physical fitness. But WADA has disagreed. The body’s president, Craig Reedie, in an open letter to The Independent, wrote that meldonium was “a big concern because it’s clear that people are abusing the drug.”

Several studies in the past year have bolstered WADA’s case. A 2015 study, funded in part by the Partnership for Clean Competition, analyzed 8,300 urine samples collected at doping control sessions and found that 182 (2.2 percent) contained the substance. A study of last year’s European Games in Baku, Azerbaijan, published Wednesday in the British Journal of Sports Medicine, found an “alarmingly high prevalence of meldonium use by athletes.” According to the study, 13 winners or medalists were taking meldonium, and 66 athletes tested positive for it.

Growth in the use of meldonium, particularly among Eastern European athletes, was a subject of the latest documentary from the German network ARD, which first reported on systematic Russian doping in 2014. The investigation cited a 2015 Russian study that found meldonium in 17 percent of 4,316 urine samples tested.