Most people walk about 65,000 miles in a lifetime. It's worth a few extra miles to see the current exhibition, "The Great American Foot," at the Museum of Contemporary Crafts.

Such shows, singling out imaginative themes, have become a signature of this small museum down the block from the Museum of Modern Art. In the past they have paid homage to beds, bags and doors; and like the others, this one touches on the art the subject has inspired, practical and not-so-practical foot coverings, celebrity shoes and, in an accompanying catalogue, a lot of the marvelous superstition and customs about feet and shoes.

The biggest shoe in the show is Ann Slavit's nylon ripstop pneumatic structure near the entrance, ceiling height and five feet in diameter, and the smallest, perhaps even smaller than the shoe for a bound foot in 19th-century China is Agnes de Milles' satin toe shoe, size 1 1/2.

If the show has a weak suit it is the historical part, both in the small numbers of truly old shoes and in the presentation, which has the potential of telling the changing role of women through the shoes they wore. Admittedly, old shoes are hard to come by and the catalogue does well in filling in with the history as well as the customs of shoe-wearing.

The earliest shoe in the show is a 16th-century Venetian "chopine" with a 5 1/2-inch platform. They were first worn by the grand ladies of Venice to keep their skirts off the dirty streets and eventually became the common garb of prostitutes. It was only when there were so many accidents of women tipping over, in spite of the young boys who were often enlisted to support them as they walked, that the church actually outlawed this style of shoe.

Customs and superstitions, revealed in the shoe catalogue, are a feast for shoe and foot fetishists. In Arab countries, the book reveals, a man could end his marriage by putting his wife's shoes outside his door and stating, "She was my slipper, and I have cast her off." Yet at an Anglo-Saxon wedding, the father of the bride gave his aythority over his daughter to her husband by presenting the groom with his daughter's shoe.

And the ancient Egyptians supposedly cured headaches by taking a whiff of the smoke from a burning sandal.

In the Napoleonic era, when women wore soft slippers without a heel - they rarely budged beyond the living room or bedroom so needed little more - the Empress Josephine is supposed to have scolded her shoemaker when she developed a hole in the sole of a slipper after one wearing. "Ah, I see what it is," remarked the clever shoemaker. "Madame, you have walked in them."

Shoes for walking on the moon, for running, for climbing, for all sorts of special use are in the show. But one is left hungering for the kind of exhibit put on in Montreal Expo by Ivan Chermayeff with hats, including the hats from all styles of life and professions. Imagine such a range with shoes.

The show includes that startling range of sizes American shoes are available in, 34 in all, displayed with one style of sneaker. (The sneaker is from the Kinney Shoe Corporation, which sponsored the show.) But the great variety of athletic shoes is missing, and though there is a hand-tooled boot, it might have been fun to have a well-worn variety rather than a spanking new one.

There is little that the show hasn't scouted up that even remotely relates to the foot, including photos of the Statue of Liberty, Carter's inaugural music such as "Tiptoe Through the Tulips."

While there is no place for the visitor to rest his feet while touring the show, there is one concrete reward, a machine which dispenses a free shoe shine.

The show closes July 9 and then will go on a national tour.