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 Format Distances: 40 Miles or 50 Miles Loop Length: 3.1 miles (5K) Course Type: Continuous loop trail race Time Limit: 12 hours Start/Finish: Same location each loop Aid Station: Fully stocked at every lap Staging 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 distance Athletes stepping up from a marathon or 50K Experienced ultrarunners seeking a fast, efficient course Competitors 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.