Until about a decade ago, any talk of a human finishing a marathon in less than two hours — especially on a more challenging course, like Boston’s — was largely written off as a pipe dream. But then ...

Kenyan Kelvin Kiptum broke the marathon world record to win the Chicago Marathon in 2 hours and 35 seconds, nearly breaking the two-hour barrier. Dutchwoman Sifan Hassan ran the second-fastest women’s ...