Figure skating may be among sports' harshest taskmasters. Not only does it demand audacious triumphs over gravity, but a skater must make them appear effortless. The margin of error is as slim as a blade. A skater's grace must be precise or it is nothing.

The World Professional Figure Skating Championship for the Avon Cup at Capital Centre last night brought together skaters of different styles, different eras, and different levels of conditioning. Those who had seen better days were not necessarily those who had seen more days.

There was vamping and clowning, sequins and satin. There was a hot duet skated to the rhythms of "Bolero," facilitated by a orange-yellow boa. And then there were the Protopopovs, Oleg and Ludmilla, the pairs skaters who won Olympic gold medals in 1964 and 1968. The Protopopovs, who brought classicism and line to skating, brought class and lines of autograph seekers to the competition.

It hardly mattered that their team, the All Stars, lost the competition (which will be seen on NBC television beginning in February. The All Stars, including Dorothy Hamill, 1976 Olympic champion, and Toller Cranston, the 1976 Olympic bronze medalist, led the team competition throughout the technical and artistic portions of the program.

But Cranston, who gave the best individual performances of the evening, completing three triple jumps in his emphatically dramatic style, "was at the wrong end of the ice" during the group finale, said Dianne DeLeeuw of the losers. So the Pro Stars, including Linda Fratianne, Tai Babilonia and Randy Gardner, Janet Lynn and Charlie Tickner, won by 9/100ths of a point.

They each receive $20,000. The losers get $10,000 each.

"We'll be back," said Hamill.

A promise or a threat? "Both," she said.

Hamill's competitive days are long gone. She says it took her four years not only to adjust to winning a gold medal, but to realize it. "I remember sitting in the Olympic arena in Lake Placid when the American hockey team won," she said. Her husband, Dean Paul Martin, sat beside her. "He said, 'Don't you realize you did that. You won.' I don't think I realized it until then."

Hamill, who was greeted by squeals of "We Love You Dorothy," began with "There's No Business Like Show Business."

Of course, that's the business these skaters are in. Early on in the evening, the crowd of 16,913, seemed a bit restive, waiting for someone to give them something to cheer about. They applauded their Dorothy. They were enthusiastic about Cranston's firebird suite. They could have been nicer to Tickner, whose second program (in the artistic phase) was clean and expressive, although not gaudy. The music was from "My Way," the way Tickner always skates.

They probably did not remember Don Jackson, who at age 42, skated three minutes of the program that won him the 1962 World Championship, completing a triple salchow in the process.

But just like last year, it took John Carlow, who performs for Walt Disney's Great Ice Odyssey, to shake 'em up. Last year, Carlow was a last-minute replacement for Babilonia. He showed up all the big names with the big titles. This year, he showed up with an invitation to compete.

Before the competition, Carlow admitted he was nervous about doing the technical number (a change in the rules meant there were not required moves). But he knows how to sell. "It's one on one," he said. "Those 20,000 eyes are going to be on me. I want to give out to them and I want them to give back to me."

By the time he finished his routine to the music from Zorba the Greek, with a triple salchow, piston rolls, split jumps and a final scratch spin, the crowd was on its feet.

He got more bouquets than any of the ladies.

He was followed by the Protopopovs, the Soviet champions, who defected to Switzerland in 1979. The contrast could not have been greater but the result was the same: another standing ovation.

Carlow was infectious. The Protopopovs glided and seemed to make time stand still, their bodies moving in sychronized fluidity. It was hard to know which of their programs was better. The artistic presentation was to Rachmaninoff's "Elegy." They began in unison, beings intertwined. They swirled away from each other, crossing paths, then circled each other in the middle of the ice. They turned away again. Then he reached for her and she backed toward him. She ended on his knee, her back arched to the ice, his body hovering over hers.

"People tell me I make them cry," he said. "That's my mission."

Earlier, in the technical portion, they skated to the Moonlight Sonata. "It's not too big a number, three minutes," he said. "It represents another step in our skill, a step in our skating. When you are in amateurs, it is not just skating. It is push, push, push. We wanted to freeze it for a moment. It is exciting for people, when you try to stop it for a moment and people have the opportunity to see it without the rushing."

For just a moment, she curled up against his body and clung to his shoulder as they glided around the ice in inseparable motion. At the end, he lifted her above his head with one arm, and held her aloft, a mobile sculpture. Then he gently lowered her to the ice with that one arm, in one motion.

When they were done, there were flowers on the ice for Ludmilla Protopopov, who is 47. Her husband, who is 50, swooped them up and, on one knee, presented them to her.