The Next Loop 40M/50M Challenge | Half Day Forest Preserve

The 40/50 Mile Challenge​The 40/50 Mile Challenge is a continuous loop endurance race designed for runners who want to push beyond traditional race formats while benefiting from a fully supported, centralized course.
​Held alongside The Next Loop Endurance Series, this event runs on the same 3.1-mile (5K) loop, but unlike the hourly format, competitors in the 40/50 Mile Challenge run continuously with a strict time cutoff.
​This format offers a true ultra-distance experience—simplified logistics, consistent footing, and constant access to aid and support.
​Event FormatDistances: 40 Miles or 50 MilesLoop Length: 3.1 miles (5K)Course Type: Continuous loop trail raceTime Limit: 12 hoursStart/Finish: Same location each loopAid Station: Fully stocked at every lapStaging Area: Designated personal staging area near start/finish​​
Runners complete repeated loops until they reach their chosen distance or the time limit expires.
Who Should Run the 40/50 Mile Challenge​This event is ideal for:
Runners attempting their first ultra distanceAthletes stepping up from a marathon or 50KExperienced ultrarunners seeking a fast, efficient courseCompetitors who value logistics simplicity and strong support​​
The loop format removes navigation concerns and allows athletes to focus entirely on pacing, fueling, and mental toughness.