John Wooten, the strongest man in the world, came to town the other day. He brought along his assistant, Larry Small, who got to carry a portable bed of nails and a sledgehammer. John Wooten was looking for the correct cinder blocks.

What Wooten does is lie down on the bed of nails, his assistant piles cinder blocks on his chest and then his assistant smashes the cinder blocks with the sledgehammer.

He found the cinder blocks at Betco Block and Products Inc. in Bethesda, a busy yard off River Road. A television crew from the syndicated program "World of People" was on hand to videotape performance.

To make the bed of nails stunt memorable, Wooten likes to take the top of his karate suit off so his bare back can rest against the nails. However, when he took his karate top off, he was cold. "Hurry up," he said a few times to the television crew.

Wooten is 6 feet tall and about 245 pounds. He has been a physical education teacher in Massachusetts and a public health inspector, and he is currently an instructor in the martial arts. With his shirt on, he looks like a regular guy with a large chest who is good at shaking hands. About 10 employes of Betco Block came out to watch the TV crew film his trick, and he introduced himself around. "Hi, I'm John Wooten."

It made a nice break in the day. Stephen Schuyler, a Betco Block executive, brought out a pot of coffee. Delivery-truck drivers in adjustable-band mesh caps stood around watching.

In 1976, Wooten was teaching school, and although he was not yet the strongest man in the world, he was certainly strong. Then he got sick. Doctors found a tumor on one of his lungs and operated to take the lung out. Now he has only one.

"I was lying in the hospital, feeling pretty terrible, and my father came in to see me. Actually, I was adopted, and so my father's name is Mayo Kaan, a wonderful man. Back in 1937, he was the first Superman in the movies, and a strong man in his own right. Well, Mayo brought a rock into the hospital and held it in his hand and crushed it. It broke into four or five pieces. 'When you get out of here, you're going to be the strongest man in the world,' he said to me."

Now he is, he says.

If you ask who else says he is who he says he is, he replies: "NBC's 'Real People,' Merv Griffin, "The Guinnes Book of World Records.' I've got affidavits and videotape of all my stunts.

You have to." Actually, John Wooten is not yet listed in the Guinness records book, but he will be in the next edition, he says.

"Nobody has done the feats I have," he explained. "I have proved myself with 27 world records, many of them precedent-setting. For example, I held a turbo-prop Commander airplane from taking off for 27 seconds, which was seen on 'Real People.' I used a long nylon rope, well padded, and the plane got up to full power and was bumping and skidding, but couldn't take off."

The "Real People" people thought that was great, Wooten said, because a strong man attempted to hold back a drag racer on ABC's "That's Incredible" had failed at his task.

"Also, I won a tug of war with a 4,600-pound elephant. After six minutes, the elephant collapsed from exhaustion. And I back-lifted a Harvard marching band of eight people, plus a 500-pound platform. I did them all the same day, at Worcester Airport, before a crowd of 21,000 people, for 'Real People.' There was a lot of pandemonium."

Wooten, who has also pulled a 170-ton train 10 1/2 feet at Boston's South Station and had held up a 4,660-pound Chevrolet after the lift in a gas station was lowered from it, says his secret is the "knowledge of the chi," which comes with martial arts training. "This permits great internal power. Your mind sort of separates from your body. It allows excessive amounts of power for a short period of time." He holds the rank of master technician in jujitsu and has a black belt in karate.

The Strongest Man in the World -- like the Ugliest Bartender in Queens or the Fastest Gun in the West or the Largest Oyster in Crisfield -- is unlikely to have his title challenged at close range.It might be said, however, from a suitable distance, that he cannot lift 896 pounds from the floor over his head the way Vasily Alexeyev did in Montreal in 1976.

"I'm not a weight lifter," Wooten explained. "I could probably learn it if I wanted to. What I've got is a more explosive-type power. Alexeyev has proved his strength in one particular way. I have demonstrated my strength in 27 ways. Besides, who has heard of Vasily Alexeyev?"

Wooten is occasionally subject to minor exasperation over the subject of his title. He stopped by the Silver Spring YMCA the other day, and a little crowd gathered to admire him. One admiring woman volunteered that she had been there a week before and had met the other strongest man in the world. This proved to be a conversation-stopper.

"Look," he said later on that day, reflecting on the search for a personal identity and also on the potential for fame and fortune and new shoes for his four children back home in Massachusetts, "what I really want is to become an actor who does his own stunts, like Lou Ferrigno or Arnold Schwarzenegger. That's why TV is very good for me. People like the cinder blocks and the bed of nails -- that's what I did for Merv Griffin, which you can see on April 3.And I'm in a 'CHiPs' episode next month, and I just did a film called 'Invisible Assassins.' I'm going to be in a movie called 'The First of Champions' soon.

"Why does the strongest man in the world do these things? Just because they're so unusual. The strongest man in the world is a guy who can hold back a plane, beat an elephant at tug of war, pull a train or jump out of a plane in handcuffs and a straitjacket, land in the ocean and swim seven miles to shore -- which, by the way, I have done.

"Believe me, your average guy will watch that a lot quicker than he will some guy holding a dumbbell over his head."