Shoe Upper
Constructed by stitching together the forepart, the rear part (quarter/heel section), and the tongue. The forepart corresponds to the front of the foot and the area of the metatarsophalangeal joints; it is subjected to flexing, stretching, compression, and friction during foot movement. The rear part features a molded heel section that conforms to the shape of the heel and is also subject to flexing and stretching during walking and the process of putting on or taking off the shoe. The forepart and rear part are typically stitched together at the waist (the area corresponding to the arch of the foot); in this region, the upper serves to enclose the foot and support the inner arch. Leather shoe uppers are generally lined to reinforce the material, prevent abrasion, and absorb foot perspiration.
Shoe Sole
Composed of components such as the outsole, insole, half-insole, shank, cushioning pad, and filler; these elements isolate the foot from the ground and provide a buffer against ground forces. The outsole makes direct contact with the ground and is subjected to bending, compression, friction, and various environmental factors. The insole directly bears the body's weight and transfers the load to the outsole and heel; in addition to bending, compression, and friction, it is affected by foot perspiration as well as internal humidity and temperature. The shank is secured between the insole and outsole at the shoe's waist to reinforce the rear section and support the arch, providing the waist with a degree of elasticity while maintaining the position and shape of the sole and heel. Cushioning pads and fillers are used to level the area where the upper meets the insole, thereby enhancing the sole's cushioning and thermal insulation properties.