There were few participants in the Tour de Ski who were still standing after the finish of that race’s final stage, the brutal ascent up the Alpe Cermis in Italy. But an even more difficult challenge may await those athletes next season: the inaugural Uphill Trophy, a new competition format tentatively slotted into the World Cup calendar in Poland next February. The race packs a whopping 500 meters of climbing into its first four kilometers—nearly...