Watching Their Steps

To put at ease those of us who had not had the operation done before, Costill explained that an area on the outside of the calf would be anesthetized. A quarter-inch incision would be made and special needlelike instrument inserted into the muscle, where it would snip out a cross section of a number of fibers. "This is to give you an idea of the tiny amount of tissue we extract," he said, and onto the screen came a picture of about six pounds of perforated liver.

When order had been restored, Costill reassured us that the bit of muscle lost would be regenerated within a month or two. "We've sampled some runners 20 to 30 times, and they're running better than ever."

"They're lighter," said Prefontaine. "I'm leaving."

In fact, he went first. Mike Manley, the Olympic steeplechaser, accompanied him and returned, excited, to tell us about it. "Pre thought the alcohol prep they rub on your leg before starting was anesthetic. 'More, more,' he kept saying. I can still feel it.' Then when the real anesthetic needle went in, he hollered, 'Wait! I can still feel!' "

Prefontaine, the most visibly defiant of an aloof breed, was a man who developed his loyalties on his own terms. Having been so much in demand for five years as the country's best distance runner, he had become sensitive to being used for the benefit of others. As the Dallas weekend wore on and he got to know the researchers, one could see his commitment growing. But coming out of the biopsy room he said, "I wouldn't do that again. It wasn't when they cut the skin initially, but when they cut inside, when they dug it out."

After the last man had limped away, Costill observed that runners were far less squeamish than any other group. "They're best at this because they are good at controlling their bodies." He agreed with the runners' view that simply knowing what to expect is the key to overcoming discomfort, not any sort of innate high pain threshold. Inuring oneself to the pain of running hard is a trick born of practice, not something given or denied at birth. "The threshold concept is a cop-out," said Prefontaine.

When Costill's analysis was complete, it was clear that we had substantiated the fast-slow twitch theory. Gary Tuttle, a rapidly improving long-distance runner from Ventura, Calif., proved to have 98% slow-twitch fibers. Olympic 10,000-meter runner Jeff Galloway had 96%. Men whose best races called for more speed turned out to have the cells for it. Three-miler Paul Geis of Oregon was 79% slow, 21% fast. Prefontaine, a 3:54.6 miler, was 77% slow, 23% fast.

So can we now sample a child's muscle tissue and judge the stamina of the adult? Not quite. Every runner's fiber ratio fits the expected pattern but one. Don Kardong, an amiable sixth-grade teacher from Seattle, one of half a dozen Americans ever to break 13 minutes for three miles and a good marathoner, had only 53% slow-twitch fibers. "But his slow fibers were large," reported Costill. Strangely, Kardong is not known for a blazing finish, while Galloway, calling on but 4% sprint fibers, is dangerous over the last lap. Thus, judging a distance runner's prospects solely from his or her endowment of slow-twitch fibers is no sure thing. But the average for the best men distance runners in the U.S. is 79% slow, 21% fast, a finding that certainly lengthens the odds against athletes with sprinters' gifts becoming accomplished distance runners.

Each participant in the Dallas study was lodged with a member of the Aerobics Activity Center. It was late that first night when I limped into the home of Harriett and Calvin Cooper. I was to fast until the following day's blood tests, so there was little to do but sit wanly for a few minutes and go to bed. The anesthetic was wearing off. My calf was stiffening and beginning to throb. As Harriett showed me to the guest room I sensed a stickiness in my lower pants leg. I drew up the cuff and found a rather rapid crimson stream flowing from the taped incision down into my shoe.

Perhaps it is kinder to pass over the ensuing few seconds of clamor and faintness. In the bathroom, brief pressure stopped the bleeding. Once into bed I remembered I'd promised to call home. I picked up the extension on the night table and heard Harriett, her voice filled with maternal compassion, say, "He's wounded, and they won't let him eat, and the poor man is already so skinny I don't see how he can stand...."