Not long ago, a group of aging elite distance runners got together, and as they reminisced about old times, a familiar topic arose: No matter how much they train, no matter how much they push themselves, their best times are behind them.
Howard Nippert broached it first. He was running the other day, he told his friends, and feeling as if he was in the groove, feeling great, just flying along as he did in the old days. Then he made the mistake of looking at his watch. It was telling him something a lot different than what he was feeling.
“I know exactly how you feel,” said his friend, Steve Spence, who is 53. Both men are…