In rock climbing a slab climb is a type of climbing route where the rock face is 'off-angle' and not fully vertical. While the softer angle enables climbers to place more of their body weight on their feet, slab climbs maintain the challenge by having smaller holds. Some of the earliest forms of rock climbing were on large easy-angled slabs encountered by climbers while mountaineering, however, the introduction of advanced rubber-soled shoes enabled climbers to use the technique of 'smearing' to ascend steeper and blanker slabs.