Tomorrow I will be running at Huntsville State Park in Rocky Raccoon, the second run in the 50 Mile Texas Style Grand Slam. (Palo Duro was the first.) A friend of mine, noting my "fetish" for 50 mile races, gave me some background on 50 mile races. I had no idea that these races follow a historical connection from Teddy Roosevelt to John F. Kennedy.
In 1908, President Roosevelt issued an executive order mandating that military officers walk 50 miles. Kennedy decided to see how the 1963 military measured up, and, given Kennedy's desire to promote physical fitness among all Americans, the 50 mile walk spread to civilian life. Bobby Kennedy put on his leather dress shoes and walked 50 miles in the snow in 17 hours 50 minutes. Boy Scout troops, college students, and communities took up the challenge. For a few months, there were 50 mile walks all over the place.
After Kennedy's assassination, the 50 mile movement all but died out. The JFK 50 Mile in Maryland is the last relic of that movement, but one could assume that 50 mile races run around the country can trace their heritage, at least in part, to Kennedy's challenge.
For a fuller story, here's the link the my friend gave me: The 50-Mile Hike Phenomenon