If you have 10 minutes, it won’t be wasted on this video. This is an ESPN segment from 1985, which covers a 30 k freestyle World Cup race in Biwabik, Minnesota.
It’s real cold on this day (-5 F) and these guys are just getting into skating. But the snow is so cold and slow that the racers revert to a good ol’ fashioned herringbone on all the steeper climbs. If you ask me, this race, and these racers, are the definition of “tough.”