THE talk, at the Expo Center at the Boston Marathon this year, had an intriguing title: Using Biomechanics to Predict Running Injuries. And the lecturer, Dr. Thomas W. Vorderer, a podiatrist at the division of sports medicine at Children’s Hospital, one of the Harvardhospitals, spoke with great conviction.
You can prevent injuries, Dr. Vorderer said, or, if you get them, can make them heal if you learn the right way to stretch and if you stretch regularly. And you should also learn the right way to run; in general, he said, runners should …

“If your goal is to finish, you just need to skate enough so that you can cover the distance. If your goal is to be faster, you have to train.”
There are training programs everywhere — in magazines, books, on the Internet. But eventually, exercise physiologists say, most people need guidance from a group with experienced coaches, like the one Mr. Gordon joined, or from personal coaches.
Training, though, can require such a commitment over so many years that many drop out. Not Mr. Gordon, who loves to train. And that love …