A peppy smile and a Spandex suit does not an aerobics teacher make.

That's today's first lesson in fitness from Charlene Prickett, 43, the TV exercise queen who for 14 years has kept millions pumping, puffing and hanging in there.Prickett, hostess of "It Figures," a popular half-hour exercise program seen weekdays on cable television, is considered one of the most knowledgeable aerobics teachers. Her exercise book, videos and classes have been hailed as models of good sense and safety.

And Prickett would like to see fewer but better-paid and better-educated aerobics instructors serving a more discriminating public.

People need a license to style hair, but aerobics is an unregulated industry, she said. "I'm afraid a large segment of the population judges fitness by dollars and cents." If you're getting instruction from a franchise that charges $20 for life, you're probably getting what you paid for, she said.

When you choose an instructor, look for certification by the American College of Sports Medicine, the Institute for Aerobics Research or the International Dance Exercise Association, she advises.

Spotting bad technique is difficult for the untrained, she said.

"But I'd be concerned about people who don't do warmups or do intense stretching during warm-ups - that should be done after exercise when blood flow is at its maximum level and the muscles are flexible."

She said aerobics instruction, in general, is making great strides, especially since hospitals and universities have been getting involved.

She thinks the future will put more stress on cross-training - doing aerobics one day, weight training the next, swimming the next, for example. It helps people avoid injury and the variety keep them from burning out, she said.