Relentless Run & Ruck Challenge

OCT
24
2026
A trail event at Camp Greenough offering a 5K loop, a 10K two-loop option, and a six hour endurance challenge. Participants may run or ruck with specified weight standards and complete as many closed-course loops as they choose.
Sat 24 Oct 2026
10 kilometers 5 kilometers

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Relentless Run & Ruck Challenge

The Relentless Run & Ruck Challenge is a trail endurance event held on the trails of Camp Greenough in Yarmouth, MA. The course is an approximately 5k loop composed of access roads and single track on a fully closed course. The looped format uses a shared central hub called Relentless Basecamp where participants doing multiple loops can keep supplies, rest, and transition between laps.

Participants choose between running or rucking. Event options:

  • 5K: one loop
  • 10K: two loops
  • Relentless 6 Hour Endurance Challenge: complete as many loops as possible in six hours

The 5K and 10K are ranked by fastest finish time. The six hour event is ranked by total distance completed with only complete loops counting; ties are broken by the fastest final completed loop.

Ruck divisions have weight standards and rules. Required ruck weights are dry weight only: men 30 lb, women 20 lb. Required weight must be non consumable and non wearable, and extra gear such as food or water counts as additional weight. Weight must be carried on the back in a traditional ruck or backpack; plate carriers, sling bags, and duffel bags are not allowed. Rucks will be weighed before the start and may be weighed at the finish. Participants may remove their ruck on course but may not make forward progress without it on their back. No trekking poles are allowed.

This event is sanctioned and insured by USA Track & Field. Visit the organization's website for the most recent information.

10 km
10k Ruck
10 km
10k Run
5 km
5k Run
5 km
5k Ruck
6 Hour Ruck
6 Hour Run
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