Trampers Friend has teamed up with SOCKSpacific Ltd of Christchurch New Zealand in producing a NEW ZEALAND MADE sock designed especially for hikers. SOCKSpacific Ltd have worked closely with a company called Nuyarn in the development a twistless wool yarn which reduces friction and the possibility of blisters.
Friction blisters usually form only on the palms and the feet. They form when the skin cell layers beneath the surface area are subjected to shear forces that result in the separation of one layer of cells from an adjacent layer. Friction blisters only form where the outermost layer of the skin is tough enough to not be ruptured by the blistering stress, resulting in an enclosed blister.
Attempts to prevent blistering focuses on the effort to reduce the skin’s coefficient of friction, either directly by the use of lubricants, or indirectly by trying to keep the foot fry (moisture tends to increase the skin’s coefficient of friction). Alternatively, the sheer force can be absorbed by an insole or sock with sufficient thickness and appropriate mechanical properties.
In order to absorb shear forces, a sock should ideally retain pile thickness under compression while being relatively easy to displace sideways when the force is applied. Hygroscopic fibres, such as wool, provide a drier environment inside impermeable footwear like hiking or skiing boots. Combining these two mechanics, a twistless yarn construction can be expected to bring the best results; with the fibres being oriented perpendicular to the sole of the sock (thus providing the best resistance to compression) but still being able to be pushed over by a transverse shear force. The sock helps prevent the force being transmitted to the foot.