Experimental and Theoretical Predictions of Static Plantar Pressure of Socks with Different Stitch Lengths.

BACKGROUND: Socks are mainly used to give the foot more comfort while wearing shoes. Stitch density of the knitted fabric used in socks can significantly affect the sock properties because it is one of the most important fabric structural factors influencing the mechanical properties. Continuous plantar pressures can cause serious damage, particularly under the metatarsal heads, and it is deduced that using socks redistributes and reduces peak plantar pressures. If peak pressure under the metatarsal heads is predicted, then it will be possible to produce socks with the best mechanical properties to reduce the pressure in these critical areas. METHODS: Plain knitted socks with three different stitch lengths (high, medium, and low) were produced. Static plantar pressure measurements by the Gaitview system were accomplished on ten women and then compared with the barefoot situation. Also, the peak plantar pressure of three types of socks under the metatarsal heads are theoretically predicted using the Hertz contact theory. RESULTS: Experimental results indicate that all socks redistribute the plantar pressure from high to low plantar pressure regions compared with barefoot. In particular, socks with high stitch length have the best performance. By increasing the stitch length, we can significantly reduce the peak plantar pressure of the socks. Correspondingly, the Hertz contact theory resulted in a trend of mean peak pressure reductions in the forefoot region similar to the socks with different stitch densities. CONCLUSIONS: The theoretical results show that by using the Hertz contact theory, static plantar pressure in the forefoot region can be well predicted at a mean error of approximately 9% compared with the other experimental findings.

Plantar Static Pressure Distribution in Normal Feet Using Cotton Socks with Different Structures.

BACKGROUND: The major goal of investigating plantar pressure in patients with pain or those at risk for skin injury is to reduce pressure under prominent metatarsal heads, especially the first and second metatarsals. In research, the insole is used to reduce plantar pressure by increasing the contact area in the midfoot region, which, in turn, induces an uncomfortable feeling near the arch during walking. It is deduced that sock structure can redistribute plantar pressure distribution. METHODS: Seven sock types with seven structures (plain, single cross tuck, mock rib inlay, cross miss, mock rib, double cross tuck, and double cross miss) for the sole area were produced. A plantar pressure measurement device was used to measure plantar static pressure in ten participants. The barefoot plantar pressure distribution was compared with the plantar pressure distribution with socks. RESULTS: In the seven sock samples, the mean plantar pressure of the cross miss and mock rib structures at high plantar pressure zones (toe and first through fourth metatarsal bone regions) were decreased, and, as a result, the pressure shifted to relatively low pressure zones (fifth metatarsal bone and midfoot regions). CONCLUSIONS: These results indicate that wearing socks with cross miss and mock rib structures will reduce mean plantar pressure values compared with the barefoot condition in high plantar pressure zones. In general, the results suggest that mean plantar pressure is redistributed from high to low plantar pressure zones.

Effect of socks structures on plantar dynamic pressure distribution.

A major purpose of investigating the plantar pressure in patients with pain or those at risk for skin injury is to reduce the pressure below metatarsal heads, specially first and second metatarsal heads. The aim of this article is to evaluate the effects of the socks structures on the changes in plantar dynamic pressure. In this study, seven socks types with different structures for the sole area were produced. The Gaitview® AFA-50 system, a force plate, was used to measure the plantar dynamic pressure of 10 participants. The barefoot plantar dynamic pressure distribution was compared with the plantar dynamic pressure distribution with socks by two independent samples test on various zones of the foot and on different genders using SPSS software. Mann-Whitney tests were used to determine specific significant differences. The obtained results showed that the main trend was to redistribute the plantar dynamic pressure from the higher plantar pressure zones (toe and first through forth metatarsal bone regions) were decreased and as a result the plantar pressure toward the relatively lower pressure zones (fifth metatarsal bone and midfoot regions). In comparison with the barefoot condition, the cross miss structure reduced the mean pressure in the critical region of the foot (first metatarsal) for male and female subjects ( p < 0.05) and also the mock rib structure reduced the mean pressure for female subjects ( p < 0.05). In general, the results suggested wearing the socks because the socks make the plantar pressure redistributed from high to low plantar pressure zones. The results of this research indicated that wearing socks with cross miss and mock rib structures will reduce the mean plantar pressure values in forefoot area in comparison with the barefoot condition.