The gusto with which the Stuttgart Ballet lit into their season's first "Romeo and Juliet" last night was based on strong dancing. Technically, the company is in better form than on their last visit to Kennedy Center: Shoulders are proud, the footing is firm - and their material had substance. Prokofiev's score for this Shakesperian dance play is already being called a classic, although its just over 40 years old.

John Cranko, who choreographed the Stuttgart's production in 1962, was faithful to Prokofiev's vision of a Renaissance painting come to life. There is the turbulence of crowded streets, the machismo of the young bloods and the gravity of the social order. Gradually they recede, and the tragedy of the true lovers is shown, not sentimentally or grotesquely, but in stark, direct strokes.

Cranko also was faithful to the spirit of Leonid Lavrovsky, the choreographer for whom Prokofiev had written the music, though it was Vania Psota who staged the 1938 premiere in Brno, Czechoslovakia. That was a historical accident, but history intervened again and erased Psota's work with World War II. It is Lavrovsky's stage and film versions made in Leningrad and Moscow in the 1940s to which successors must be compared.

Cranko isn't as wildly romantic or grandly heroic as Lavrovsky. There is a German operatic realism in the way he blocks crowd scenes. Both choreographers loved high, long, expressive lifts, but Cranko's in the duets are not as flowing. Perhaps the strong scenic frame of a town square that Jurgen Rose designed in splendid colors hems the after-image of the dancing.

Marcia Haydee and Richard Cragun were, unexpectedly, the lovers.She is a Juliet with spunk, who takes what she thinks is pretty - whether it is a gown or a young man named Romeo. For those lifts, Haydee has a back that bends with rapture.

Cragun's multiple turns and winning manner when not acting made up for some ham. The company, though, is famous for its miming - and this reputation was upheld by Egon Madsen, Alexander Ursuliak, Ruth Papendick, Marcis Lesins and that link with the Stuttgart past, Hella Heim; all except Madsen were on the Capulet side of the stage. Friedrich Lehn conducted the great score.