Xtreme Challenge is a September OCR race held in the forests near Poznan. The start and finish area is located by the Lysy Mlyn educational center, close to Biedrusko. Participants can select a course of approximately 5+ km or 10+ km. Wheelchair users have a distinct 1000+ meter course. The event has a participant limit of 500 people and is organized by SPORT CHALLENGE Fundacja Wspierania Aktywnosci Fizycznej.
The route utilizes the forest environment extensively, with about 99% of the course on natural terrain. This includes mud, swamps, watercourses, a river, thickets, fallen trees, and uneven ground, supplemented by some artificial obstacles. The specific route and obstacle list are not revealed until race day. Participants are informed of the distance and time limits: 90 minutes for the shorter course, 180 minutes for the longer one, and 60 minutes for the wheelchair course. All finishers receive a medal. The organizer also provides electronic timing, basic medical care, a recovery meal, event photos, and baggage drop. The race supports social objectives, including promoting physical activity, highlighting local natural areas, and fostering the inclusion of people with disabilities.