This Monday the 123rd annual Boston Marathon will take place, with an expected 30,000 participants and a half million spectators. The top finishers should complete the grueling 26.2-mile course in just over 2 hours by clocking a pace of under five minutes per mile.

I know. It’s painful to imagine. Most of us couldn’t maintain that speed for one mile — forget 26 of them.

But take heart, recreational runners of the world. Your endurance abilities are actually extraordinary, when compared