"I FEEL that I understand the problems of dancers because I am very sensitive to the needs of artists," says Marta Istomin, the artistic director of the Kennedy Center. The future of ballet and all dance at the Center is in her hands, and last week she discussed what that future might hold.

"I think of myself as first of all a musician, an artist," said the 43-year-old former cellist. "So I understand the needs of other artists for the essentials of their craft, and for proper atmosphere. Some things are absolutely basic. A musician needs a good instrument, and adqueate rehearsal time. And dancers must have a good floor."

On that subject, Istomin is clearly elated to report some progress on the matter of the stage floor in the Kennedy Center Opera House, where major domestic and visiting ballet troupes customarily appear. The hardness of the floor -- a circumstance both hazardous and fatiguing for dancers -- has been recognized as problematical since the Center's opening in 1971. But nothing has been done about it until now.

"I had gone through all the archives, and knew that despite the knowledgeable advice obtained when the Opera House was built, things didn't work out satisfactorily. Only a few weeks ago, we authorized the construction of a new type of removable floor covering, designed by our technical consultant Alex Morr and an associate of his. There were discussions, too, with American Ballet Theatre and New York City Ballet over what was needed." The new floor comes in layers of rubberized cushioning, but it only raises the stage level 2 inches, and its sections interlock in such a way that there are no joints or pegs underfoot. The installation will not require shutdown of the Opera House -- a big obstacle in the past -- and instead of costing hundreds of thousands, as resurfacing the stage would, the cost will be under $100,000.

The innovation was tested last Monday by five dancers from ABT who flew down for the purpose, and the results were very encouraging, as Istomin said afterward. "The dancers liked it and said it was a great improvement. They made some suggestions to Morr, involving relatively minor adjustments. They're coming back tomorrow with some New York City Ballet dancers this time, we hope, to try again. At this point it's still only a possibility, but if things work out, we'll make every effort to have the new flooring in place for the ABT engagement here in December. And should it not work out, for whatever reason, we'll look further -- I'm determined to find a solution."

As to the overall future of dance at the Center, Istomin's long-range plans have yet to be amply formulated. Nevertheless, it's clear that a great many particulars are receiving attention.

"We are fully committed to a second year for our new joint venture with the Washington Performing Arts Society, the Dance America series," Istomin says. "What's difficult is to be fair to everything that's happening in dance these days -- there's so much. The series is very expensive and means a large deficit, but I think it's our responsibility to reflect all trends in dance, including much that is new, and we'll just have to find ways of financing this. i

"Another way we want to expand is to be able to bring some American ballet companies from across the country here -- we've been looking at companies like the one in Utah, the Boston Ballet, the Pennsylvania Ballet and the San Francisco Ballet. This doesn't mean we don't want to continue bringing fine foreign troupes, but for the near future, anyway, because of the great financial burdens, the only way we can do this is in conjunction with the Metropolitan Opera. We are thinking about the Royal Danish Ballet and the London Festival Ballet, for example, for coming seasons. And we are exploring many others, both here and abroad."

Istomin sees no contradiction between the Center's role as a national showcase and the appearance of artistically worthy local dance troupes in its halls -- "we should be supporting whatever is artistically valid," she said, adding that she's well aware that the Washington Ballet, for instance, which has had successful performances in New York, has yet to make it to the Center.

For the moment, Istomin has no plans to hire a dance specialist for the Center staff, preferring to consult with a variety of people in the field for expert advice.

Among potential developments relating to dance at the Center that Istomin is pondering are festivals -- Stravinsky and possibly Haydn for '82; Brahms for '83; Bach for '85. Her outlook is distinctly positive. "I'm an optimist," she said, "and I firmly believe awareness of the arts in America has reached a point where we'll have to keep them growing no matter what the difficulties."