When he portrayed Flash Gordon, Buster Crabbe vanquished Ming the Merciless, evil Emperor of the Universe. As Tarzan, he outwrestled lions and crocodiles. As Buck Rogers, he conquered Killer Kane and his robot battalions. And as Billy the Kid, he hog-tied enough villains to last through 36 pictures.

Now, at 68, Crabbe is battling a more formidable foe: old age. Looking nearly as fit as the 23-year-old Clarence Crabbe who won a swimming gold medal in the 1932 Olympics, Buster has written a book on physical fitness for the Medicare set entitled Energistics. He has also become a proselytizer for the exercise and diet it prescribes.

Crabbe awakens most mornings by 5:30 with sit-ups, leg raises and a light workout. Then he swims and when he's home in Scottsdale, Ariz. often puts in a day of yard work.

Recently Crabbe has hit the road as a recycled star on the nostalgia circuit. Flash Gordon, a late-'30s movie serial, has been revived with considerable success on TV. The show has boosted his stock as a lecturer on campuses where, among other things, he satisfies undergraduate curiosity about the identity of Flash's enemy, the Orangupoid. It was a man in a costume, Buster explains patiently, not a real gorilla with a horn pasted on its forehead.

Born in Oakland, Crabbe grew up in Hawaii, where his father was a plantation overseer. Returning to the mainland to attend USC and then law school, he became a world-class swimmer almost without trying. "In those days," Buster recalls, "we'd swim an hour or two a day and that was it. That's just a warm-up today." In the 1928 Olympics in Amsterdam, he took a third in the 1,500-meter freestyle, and four years later in Los Angeles won the 400-meter gold medal. Before retiring Crabbe set 16 world records.

He had worked as an extra and a double while at USC and screen-tested for MGM's first Tarzan talkie, the role Johnny Weissmuller got. When Paramount began looking for a competitor to Tarzan in 1933, it recruited Crabbe, making him Kaspa the Lion Man in King of the Jungle. (Later he succeeded Weissmuller in one Tarzan picture.)

Calling himself Buster, a real-life nickname given him by his father, Crabbe began a 30-year career in movies that was largely forgettable. But reviewing King of the Jungle, TIME commented, "From the neck down Crabbe easily equals Weissmuller as an attraction to female audiences; from the neck up he is a vast improvement." Indeed, critics usually praised Crabbe's acting. That's why it still upsets him that he was doomed to grade-B action movies. "I always wished I could have been in one really good film," he sighs. "But they decide you're a guy who can fall off a horse and take a breakaway table over your head and there's nothing you can do about it."

In the mid-'50s he had a TV series hit, Captain Gallant of the Foreign Legion, with his young son, Cuffy, as co-star. (Crabbe and his wife, Virginia, have been married 43 years; in addition to Cuffy, now 31, they have a daughter.) The series ran two seasons. The only film he has made since 1965—The Comeback Trail in 1971—was never released.

He always cultivated interests outside movies. Early in his career he swam in aquacades; later he briefly worked as a stockbroker, and he continues to endorse a line of swimming pools. Now he is dedicated—not without a smidgen of vanity—to his fitness campaign. As he travels, he has come to expect one question: "If you're so healthy, how's your sex life?" "Fine," Crabbe replies to what is always a younger interviewer. "How's yours?"

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