Jeannie Rice is faster at 71 than she was at 70. In October 2018, she stunned the running community when she broke 3:30 for a marathon, running 3:27:50 in Chicago. On September 29, almost one year later, she broke her own 70–74 world record in Berlin, running 3:24:48. She averaged 7:49 per mile. Rice, who splits her time between Mentor, Ohio, and Naples, Florida, ran even splits most of the race. All her 5Ks were in the 23-minute range, until the 35-kilometer mark (about 21.7 miles). Then she slowed to a 26:34. “I faded the last 5K, but I knew...