His projected time — 3:20 to 3:30 — would probably place Kennedy among the top 5,000 finishers in Sunday’s field of about 50,000. But his motivation would be familiar to a first-timer in the back of the pack — drop a few pounds, stay healthy for his children, reconfigure his life after a recent divorce, run for fun, gain a sense of accomplishment without a need for victory or personal records.

“This is, for me, finding myself again through running,” Kennedy said in an interview last week.

In his prime, Kennedy held American records at 3,000 meters (7:30.84), two miles (8:11.59) and 5,000 meters (12:58.21). Running was a consuming emotional investment. He was intensely competitive, training twice a day, nearly every day, running up to 130 miles a week. He found it to be a life of necessary selfishness, everything focused on his career, which brought great achievement but came with a price.

“I think I’ve found a balance,” Kennedy said. “I’ve found I can do things in my life for reasons beyond just being successful.”

Upon retirement, Kennedy had little interest in taking a two-hour run for the sake of it. After five years of inactivity, he began running again for a half-hour at a time, but only intermittently, starting for two or three weeks, then stopping for eight or 10.