Mark Kiptoo has had some pretty memorable trips to Frankfurt. He won the city's marathon in 2014, returned four years later to set a then-world record for runners over 40, and on Sunday added another achievement to the list. This time, at 50 years old.

The Kenyan distance runner finished the Frankfurt Marathon on October 25 in 2:15:24 , averaging roughly 5:10 per mile across 26.2 miles. He placed 13th overall, but his performance was particularly impressive for another reason: It was the fastest marathon ever recorded by a man in the 50–54 age group—and it wasn't especially close.

For 35 years, the M50 record belonged to South Africa's Titus Mamabolo, who ran 2:19:29 in Durban in July 1991. Kiptoo cut four minutes and five seconds off that mark on Sunday, a substantial improvement that now awaits official ratification by World Masters Athletics.

Kiptoo has barely had time to get used to being 50. He celebrated his birthday on June 21, less than two months after finishing 2:12:21 at the Geneva Marathon.…