“I’ve tried to get one of their top coaches and athletes here as one of my assistants for years,” said Steve Fraser, a 1984 Olympic champion in Greco-Roman wrestling and the head coach of the national team for 18 years, who is now the chief fund-raiser for USA Wrestling. “It has been impossible. I’m hoping that will loosen up.”

Efforts underway by the United States Commerce Department to lift export barriers on construction and sports equipment will be welcomed in Cuba. At some provincial stadiums in the Cuban baseball league, balls can become so scarce that games stop while children retrieve home runs and fouls and return them to the umpires, said Robert Huish, an assistant professor of international development studies at Dalhousie University in Halifax, Nova Scotia, who studies Cuban sports.

Rain can leave the wrestling mats soaked at the Greco-Roman training center, said Fraser, who travels here yearly. When the United States played a soccer match in Havana in 2008 while qualifying for the 2010 World Cup, a downpour left the field looking “like a cow pasture,” said Don Garber, the commissioner of Major League Soccer.

“Sport is the victim of limitations of the embargo,” said Tomás Herrera Martínez, the director of international relations for Cuba’s sports ministry and a bronze medalist in basketball at the 1972 Munich Olympics. “Sport is one of the main rights of the people, but sometimes there have not been enough resources.”

Baseball is Cuba’s most popular sport, but it has been dropped for now from the Olympics. Boxing, with its numerous weight classes, has long been the country’s most reliable producer of gold medals; Cuba has won 34.

Teófilo Stevenson, a heavyweight who won three golds from 1972 to 1980, once gave a short and loyal explanation about why he would not leave Cuba for the riches of professional boxing.