Manning D P, Cooper J E, Stirling I, Jones C M, Bruce M, McCausland P C
J Hand Surg Br. 1985 Oct;10(3):303-7. doi: 10.1016/s0266-7681(85)80049-8.
The incidence of slipping accidents is unknown, but accident and emergency departments in the United Kingdom probably treat over one million injuries per annum caused by slipping of the feet. Many injuries to farm livestock are caused by slipping. Previous research led to speculation that some animal species may have developed slip-resistant feet and the polar bear was chosen for a study of adaption to a slippery environment. Feet were photographed and a footpad was sectioned and examined by light and electron microscopy. Hardness of the footpads of two tranquillized bears was measured. The footpads were found to have a rough papillary surface overlying a soft dermis containing a dense network of collagen and elastic fibres. These findings support a hypothesis that shoe solings for use on an icy substrate should be soft with a hardness value in the region of 24 on the Shore A scale. The surface should be covered in conical projections having a mean diameter of 1 mm. Further work on the feet of animal species could lead to a better understanding of slip-resistance and reduce injuries to humans and livestock.
