"Water exercise: the wave of the future!" declared Terrell Dougan, an instructor at the beautiful new Steiner Aquatic Center, 645 Guardsman Way.

There are innumerable benefits to water exercise, as thousands of enthusiasts all over the city will tell you.But you're waiting to "lose those 10 pounds" before you subject yourself to public gaze in a swim suit? That's how you're going to lose the 10 pounds, turkey! Anyway, few real water enthusiasts swim in fashion suits. They are more likely to be found in a shapeless tank, a Speedo or a durable Iron Maiden constructed of 100 percent polyester.

Robynn Masters is supervisor of the Steiner Center, and four instructors - Dougan, Dorothy Mullins, Carolyn McClellan and Anita Dobson - teach classes in water aerobics, water walking and aqua power (building speed and stamina).

Dougan has high hopes for the center's attaining national stature. "We are working for national certification, through the Aquatic Exercise Association and the United States Water Fitness Association, both of which are dedicated to building and maintaining high quality of programs," she said. "We'd like eventually to have national conventions here."

The sun glinted off the snow on a beautiful winter morning when we visited the Silver Splash class, held Monday-Wednesday-Friday from 10:30 until 11:30 a.m. It offers a "moderate to vigorous workout to Broadway music" for seniors and others with free time in the morning.

"The class has shrunk since fall - we used to have as many as 30, but some of them have gone places like Palm Springs for the winter," said Dougan. We thought that at that moment the sunlit Steiner Center, with water temperature of 83, seemed a lot like Palm Springs.

Women in the Silver Splash do water aerobics, play exercise games, work on flotation devices and do a few water ballet routines.

"This class satisfies Esther Williams fantasies, makes you feel like you're in the movies," said Dougan. "And no one can join the class who hasn't heard of Esther Williams!"

There are many advantages to working out in the water, Dougan pointed out. "The continual resistance of the water is in itself good exercise, without muscular strain," she said.

("Just being in the water causes you to exercise," says one authority. "The continual pressure on your body makes you resist by `pushing out.' Ninety percent of your body is buoyant in the water, so you are not hitting the floor of the pool as hard as you would out of water, not smashing your joints or muscles.")

"The only thing that gets sore is your calves, and if you dance on your toes, even that doesn't happen," said Dougan.

The class also does some water walking, an exercise that is currently gaining in popularity. (See boxed information.)

The Steiner Aquatic Center has a class devoted specifically to water walking, on Tuesdays and Thursdays from 9 to 10 a.m. Although you could devise your own routine, it would probably be beneficial to take an introductory class to familiarize yourself with a variety of routines, then you can go ahead on your own - in a private pool, at the spa, or any public pool or gym.

"Water has been highly regarded from ancient times for its healing properties," Dougan commented. "The Romans were addicted to it, and people long before them."

Almost everyone in the Silver Splash had healed an injury with swimming or significantly strengthened herself. Several of the women told success stories after class. "There's nothing better for body toning and cardiovascular strength," said C.C. McClellan. Betty Greenhalgh has greatly increased strength in her upper arms and wrists, through five years of water aerobics. And Gerry Smith has a straighter and stronger back and legs, after only eight months in the class. "Water aerobics is a wonderful way to recover from Caesarian section surgery," said Jane Haugsoen.

Instructor Dorothy Mullins applauded the positive results of water aerobics. "We're not after glamour, but fitness," she said. "It makes you able to hike to the top of a mountain and down, and play with the grandchildren. And laughter is a big part of this class. It's fun, and it's good for you."

*****

(Additional information)

Walking through water can keep you strong, well and young

Suggestions for water walking from the United States Water Fitness Association:

- No, you are not expected to walk on the surface of the water; you should walk in water waist- to chest-deep for maximum benefits, which include improved fitness (but only if you exert real energy); helping to recover from accidents and sicknesses, and combatting the aging process.

Many people with physical disabilities can walk in water, where they could not on land. It's playful, easy exercise, where you can be with friends, meet new people, relax and reduce stress.

Remember the cardinal rule - never begin an exercise program without the approval of a medical doctor.

- Work into water walking gradually, allowing the body time to accustom itself to unfamiliar exertion. Water walking should be done from three to six times a week, with a warmup period, a main session and cool down, to let the heart gradually return to resting rate.

- The U.S. Water Fitness Association suggests that water walkers be creative in their routines. You might like to walk forward, backward or sideways, using a variety of steps - regular, short and quick, or long. Walk backward, using the same sequence of steps, and being careful not to overdo the long steps.

Or you can do step-kicks, either forward or backward; touch your toe with your hand when you kick, using one leg only for the length of the pool or alternating legs. Try knee touches, touching the opposite knee with hand or elbow. To add to the workout, move your arms in a variety of ways, keeping your hands under the water for maximum effect.

Then there are sidestepping possibilities, first to one side or the other, using average-size steps, or grapevine steps, or lunging first to one side, then the other. With so many possibilities and combinations, water walking need never be boring.

- Be sensitive to the dictates of your body, listen and watch for warning signals such as abnormal heart action, chest pain, dizziness, confusion or other signs of poor circulation; flareup of arthritis, nausea, shin splints and other such symptoms, which may mean that you should modify and move a little more quietly to begin with.

Some helpful hints:

- Walk all the way through your foot - heel-to-toe walking forward and toe-to-heel walking backward.

- Walk or jog an equal number of laps forward and backward, to exercise opposing muscle groups equally.

- When walking sideways, face always in the same direction, whether walking to left or right, or you won't work both legs.

Swimming is among the best exercises, but many people don't know how, or their skills are rusty, or they resist getting in the water. For them, water walking can serve as a reconnecting link to full water activity.