The scientific debate has continued about where to draw the line between fair play and the right to compete. A 2009 study published in The Journal of Applied Physiology said Pistorius could take his strides more rapidly and with more power than a sprinter on biological legs.

Some resistance remains to his presence in London, where Pistorius will also run in the 4x400-meter relay. Michael Johnson, the world-record holder in the 400 at 43.18 seconds and a two-time Olympic champion in the event, now retired, said recently that he considered Pistorius a friend and a great ambassador. But Johnson also said, “Because we don’t know for sure whether he gets an advantage from the prosthetics that he wears, it is unfair to the able-bodied competitors. “

On Saturday, Kirani James of Grenada, the reigning world champion at 400 meters, said of Pistorius: “He created history. I have a lot of respect for the guy. It takes a lot of courage, a lot of confidence, to do what he does.”

But when asked if Pistorius, who is not considered a medal contender, would be so eagerly embraced if he ran as fast as the world’s best quarter-milers, James said, “That’s another story.”

Bryshon Nellum of the United States offered more unqualified tribute. While a student at the University of Southern California in 2008, Nellum was shot in his legs in a case of mistaken identity, threatening his sprinting career.