...However, a landmark study by Nacht and colleagues showed these measures may actually increase blister formation.17 They studied the effects of mineral oil, petroleum jelly and glycerin on the skin of humans and found that all three lubricants would initially reduce the friction force at the skin surface. However, after one hour of rubbing the skin surface, the coefficient of friction returned to baseline and after three hours of rubbing, it actually rose by 30 percent. This may have been due to a hydrating effect on the skin surface as the lubricant was absorbed over time.
Other topical agents that have been advocated for blister prevention include moleskin, tape, tincture of benzoin and viscoelastic dressings. However, there are no published studies to show these measures actually work. Few things applied to the feet will stay intact for more than one hour of vigorous activity. Therefore, measures that focus on footwear may be more efficacious...
... Four different sock studies have been conducted by the U.S. military in an effort to reduce the significant problem of friction blisters affecting marching soldiers.13,23-26 These studies have shown that the combination of a synthetic nylon or polyester liner with an outer padded wool sock significantly reduced blisters in comparison to the standard military sock.
The liner-sock interface typically has a lower CoF than the skin-sock or sock-insole interfaces. Therefore, the notion of setting up a low friction interface on the outside of the liner sock is validated by the end result of reduced peak shear stress on the skin surface.
Socks can reduce friction blisters on the feet by reducing moisture content and friction loads on the surface of the foot. In general, sock fibers that wick moisture from the foot surface are also the fibers that have the lowest CoF. Acrylic fibers and polyester fibers such as Cool Max® are preferred for wicking moisture from the surface of the foot. These and other synthetic fibers will also retain their shape and resist bunching and wrinkling when wet in comparison to cotton socks.
A sock with fibers that have a low CoF can reduce friction loads on the skin surface of the foot. This can be partly dependent on the sock fiber composition as well as the construction of the sock itself. Thicker, padded socks will allow internal movement within the yarn, which will dissipate frictional force on the skin surface. Also bear in mind that “double sock systems” can allow a movement interface between the layers, which can also reduce friction loads on the surface of the foot. This concept of a sock reducing friction on the surface of the foot has been recently validated in a computer model.26
Multiple interfaces are involved with shear force reduction on the surface of the human foot during running activities. The skin-sock, sock-insole, insole-shoe and shoe-ground interfaces are all various levels where friction loads can potentially be dissipated.