Fell running is a peculiarly masochistic British sport of running up (and down) hills (known as fells in the English Lake District where it originated). The running is often off track on steep, usually wet, grassy and heathery hillsides, and the shoes need to have deeply studded soles, and a close gripping fit so that they don't swivel round the foot. Such shoes are not waterproof in the slightest, but because of their light weight and good traction are often used in summer by climbers as approach shoes.