Alicia Alonso, the great Cuban ballerina who is once again making appearances is this country, has no need to prove that she is one of the supreme interpreters of the role of Giselle. From the time of her dubut in the classis vehicle in 1943, her performance has been hailed universally as both singular and sublime. An international career spanning almost four decades, filmed records and the living memories of balleton-manes further testify to the magnitude of her achievement.

Her performance in the American Ballet Theater production at the Metropolitan Opera Thursday night, however - her first Giselle in the United States in almost 20 years and her first complete account of the role since 1972 - fell short of those memories, as it almost inevitably had to.

I had seen her perform the peasant heroine of "Geselle" in person only once before, about five years ago in Copenhagen. She was certainly beyond her physical prime then, and she had not yet undergone the surgery that was to free her from severe blindness. Yet her physical strength at the time, and the power of he artistry, enabled her to sustain the demanding role without noticeable flaging. It wa an incredibly zephyrine and tender performance, certainly the most memorable Giselle in my experience.

Now, at age 56, Alonso mat simply lack the stamina for such a taxing assignment, that's the way it seemed Thursday night, at any rate. Here and there, there were marvels enough, eveon on the technical side - wonderful crisp, fluttering leg beats and a thrilling series of entrechats, softly alighting jumps. But the seamless lyrical continuity that had been the erstwhil glory of her interpretation fell victim to strain and fatigue.

The sad fact is that the body is the medium of expression in dance. However willing or sensitive the spirit, it cannot bypass this fleshly limitation. Though the conceptual outlines of Alonso's Gisell were still much in evidence, and though isolated moments in the dancing made contact with this ideal, on the whole the nobility had to be gtasped more as intention that realization.

The sheer impassioned presence of an Alonso might still have carrried the day had not other elements in the performance mitigated against this. It did not help, for instance, that the start had to be delayed baout 75 minutes while the police searched the hall after a telephoned bomb treat. Even under the best of conditions, moreover, the rhythmic flaccidity of the orchestral performance under Akira Endo's direction would have been a nearly insurmountable obstacle for any dancers.

The rest of the cast also seemed to be laboring under a pall. Jorge Esquivel, Alonso's guest partner from the National Ballet of Cuba, looked oddly mannered as a dancer and dramatically stiff becides, Kirk Peterson won deserved applause for his virtuosity in the Peasand Pas De Duex, partnering Marianna Tcherkassky. But too often his upper torso was inflexibly tense, and his steps outraced the musical phrase. Other ABT regulars, such as Marcos Paredes as Hilarion and George de la Pena as Wilfred, ssemed out of sorts, too.