The Next Loop Endurance Series | Lake Carl Blackwell November 21, 2026 | Stillwater, Oklahoma The Next Loop Endurance Series is back at Lake Carl Blackwell with two ways to challenge yourself on the trail. The Next Loop Hourly Challenge is 5K. Every Hour. 10 Hours. Complete an approximately 5K loop every hour, on the hour. Finish within the hour, recover and refuel, then decide if you’re ready for One More Loop. Run one loop or all ten. No DNF—every completed loop counts. The Next 12 Hour Challenge is continuous. Run, walk, or hike at your own pace for up to 12 hours and see how much distance you can cover. You decide when to run, rest, and refuel. Whether you’re new to endurance running or chasing your next big goal, choose your challenge and discover how far you can go. Your Endurance. No Limits. One More Loop.See All Event Posts