Tenacious Ten Endurance Challenge

Tenacious Ten Hour Endurance Challenge is held at Mynydd Troed, Pengenfford Common, near Talgarth, Powys, Wales (LD3 0EY). Each loop is about 4.3 miles (6.9 km) with roughly 1,679 ft (511 m) of ascent. The course is a fully marked loop on rugged terrain, delivering dramatic 360-degree views of the Black Mountains and Brecon Beacons, with Llangorse Lake visible in the valley.

A new format starts with a clockwise first lap, after which participants choose their direction. Open to solo runners, pairs, and teams of four, the event features a strict 10-hour cut-off, clip stations, a Refuel Zone, camping, bespoke medals, and a cup-free policy. Visit the organization's website for the most recent information.