It’s called an FKT, and here’s how it works: Pick a trail, path, or other recognizable route of a distance you can comfortably complete. (It just has to be at least five miles and interesting enough that others will want to run it.) Add it to the Fastest Known Time website (fastestknowntime.com), start your GPS watch or phone, and haul ass.

For Wes Judd, a 29-year-old River North ultrarunner who set the 36-mile Chicago Lakefront Trail round-trip FKT of 3 hours, 54 minutes, 14 seconds on March 22, a motivating playlist helps — he cued up hip-hop duo Run the Jewels — as does a mantra for when self-doubt sets in. (His may not be for everyone: “I can take more pain.”)

Afterward, upload your data to the site. If you’re verifiably the speediest to complete it, the glory of an FKT is yours. Don’t feel up to challenging Judd’s record? (The man averaged 6:33 per mile for a distance equivalent to a marathon and a third.) Try for one of these FKTs:

▶ North Branch Trail The men’s one-way record on this 20-mile stretch from Foster Avenue to the Chicago Botanic Gardens is 2:55:21; the women’s is up for grabs.

▶ Wauponsee Glacial Trail A Chicago couple completed the 45-mile out-and-back from Joliet to Custer Park in 14:19; no one-way records have been recorded.

▶ Lake Carroll Loop Head a bit west of Rockford to reach the hilly 10-mile route with a men’s FKT of 1:18:16. That’s 7:37 per mile. Piece of cake.