Dear Pentathletes: Enjoy Your Last Ride. Get Ready for the Obstacle Course.

Athletes at the Paris Games are competing in show jumping as a part of modern pentathlon for the final time.The farrago of a sport that is the modern pentathlon owes its rarefied existence to Pierre de Coubertin, the father of the modern Olympics, who, according to legend, imagined it as a test of mettle for a typical French cavalry officer. Caught behind enemy lines, such a man might have to fence with and shoot at his pursuers; run toward safety; swim across a body of water; and ride away on a random horse he happened to encounter.

But many things that made sense in the 19th century seem less persuasive in the 21st. So, drifting toward obsolescence and facing eviction from the Olympics…