TOKYO -- WHEN Naoko Takahashi flew to a record-breaking victory in the women's Olympic marathon in Sydney, Australia, last September, she had the power of tiny wings working for her. Miss Takahashi, like many Japanese long-distance runners, is a devotee of a little-known drink that its proponents believe may revolutionize sports requiring endurance and rigorous training. Sold here under the brand name Vaam, the concoction contains a synthetic version of the juice that gives Japan's giant hornets the strength to fly distances of about 60 miles a day at speeds of almost 25 miles an hour. This drink is very effective in sustaining stamina and energy, said Yoshio Koide, Miss Takahashi's coach and perhaps the biggest proponent of Vaam's benefits. "I had tried everything before tea, lemon tea, honey but nothing worked very well." Mr. Koide does not have much of a track record to support his conviction that Vaam gives his athletes an edge, and what scientific evidence of the benefits there is comes from tests done with mice.