SAINT-DENIS, France — Sweden’s Armand Duplantis, pole in hand, stood on the runway staring down a bar higher than anyone’s ever cleared. He is now the first back-to-back Olympic champion in men’s pole vault since American Bob Richards, who won in the 1952 Helsinki Games and the 1956 Melbourne Games. Duplantis and Richards are the only men’s pole vaulters with …
