May also be used if you’re substituting for the way more skilled person, but the connotation is in any case “I’m perfectly competent at this, dare I say I’m even good at this, but if I’m going on right after this guy, I’m gonna look like crap in comparison.”

The phrase is in reference to Bjørn Wirkola, a former ski jumper (struggling with Parkinson’s dementia at present) who was considered the world’s best ski jumper in the second half of the 1960s. Yeah, of course it’s a skiing thing, what else would it be!

“Jumping after Wirkola” is still a perfectly normal phrase to use today — I can find tons of attestations in news stories from the past year, used by a librarian, the head of a municipal department, a store manager, and a police officer, used in reference to themselves — but the fact that “jumping after Wirkola” is a boomer sports reference probably has something to do with why I hadn’t heard the phrase until recently.

If that surname “Wirkola” seems familiar, you may be thinking of Bjørn’s second cousin once removed, Tommy Wirkola, a Norwegian Sámi filmmaker who directed such films as Kill Buljo, Dead Snow, Hansel and Gretel: Witch Hunters, Violent Night, and Spermageddon. Bjørn Wirkola is apparently not Sámi like Tommy, but rather has “Kven roots”. The surname “Wirkola” comes from Finnish “Virkkula”.