The Next Loop Endurance Series - Lake Carl Blackwell
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The Next Loop Endurance Series - Lake Carl Blackwell
The 40/50 Mile Challenge is a continuous loop trail race held at Lake Carl Blackwell in Stillwater, Oklahoma. Runners complete repeated laps of a clearly marked 3.1 mile (5K) loop that returns each circuit to the same central start and finish area. The event runs on the same loop as The Next Loop Endurance Series but uses a continuous format and separate scoring.
The trail surface is a mix of dirt paths, grass, and lightly packed earth with gentle rolling elevation and some wide sections. The course passes lakeside terrain, open grasslands, and wooded areas and offers expansive views of the lake and surrounding landscape. Aid is available at a fully stocked station on every lap.
Runners may access personal supplies at a designated staging area each lap. Crew access is permitted in designated areas and pacers are allowed under event rules. Medical and race staff are on site throughout the event. The format has a strict 12 hour time limit and aims to simplify logistics by keeping support centralized and navigation consistent.
Distances offered for the continuous event: Visit the organization's website for the most recent information.
- 40 Mile
- 50 Mile
