Factors Affecting Pressure Comfort in Swimsuits

With the improvement of living standards, there are more and more leisure and entertainment activities for people, among which swimming has become the choice for most people, and swimsuits have become a must-have. The comfort of swimwear has become the main demand of modern consumers, not only the style and color of swimsuits, but also the comfort of swimsuits, especially for women. The comfort of garments includes thermal and wet comfort, contact comfort and pressure comfort. Generally speaking, swimsuits that fit your body well are good for water sports, so swimsuit comfort is mainly studied in terms of pressure comfort. Clothing has a great influence on human pressure, so the comfort pressure limit of the human body must be considered when designing clothing; the pressure comfort of clothing must be predicted from the aspects of physics, physiology and neurophysiology. If the clothing pressure on the human body is higher than the load range that the human body can bear, or if the pressure increases in some parts, a series of negative effects will occur.
 
Pressure comfort of clothing
Pressure comfort of clothing is an important factor in determining whether the wearer is comfortable or not. It refers to the comfortable range of skin pressure caused by the interaction between clothing and human skin, including the fitness of the clothing and the degree of freedom of movement and other mechanical aspects of comfort. Clothing pressure directly affects the movement and physiological function of the human body. Clothing pressure is the pressure generated by the clothing acting vertically on the human body. It is the pressure generated by the combined action of the clothing's gravity and the tension generated by the elongation and deformation of the clothing fabric. A certain degree of clothing pressure is beneficial, but excessive pressure will lead to deformation of the human skeleton, displacement of internal organs and restricted breathing, which is harmful to health. During swimming, wearing a swimsuit with moderate pressure has a protective effect on the human body, which can reduce energy consumption and soreness caused by water resistance, reduce fatigue, improve exercise comfort, and increase exercise endurance. The comfortable pressure range of each part is shown in Table 1, among which the more comfortable clothing pressure range of the human body is 1.96 to 3.92kPa. The pressure comfort range of the swimsuit is 980.7 to 1961.3Pa. When choosing a swimsuit, you should consider the pressure comfort limit, pay attention to the biaxial stretch and elastic modulus of the fabric, and follow the principle of fitness and comfort. Too big swimsuits will be easy to take water, increasing the burden on the body and the resistance when swimming. Too small swimsuits can easily cause strangulation marks to the limbs and poor blood flow. Therefore, pressure comfort should not be underestimated in the comfort and functionality of the entire swimsuit.
 
Table 1 Reference value of pressure comfort in each part

 
1. Factors affecting pressure comfort in swimsuits
The research object of clothing pressure comfort is human, clothing and environment, and the three are interdependent and restrict each other. The factors affecting the pressure comfort of swimsuits include the amount of relaxation of the clothing and the extensibility of the fabric, the human body surface and the elastic coefficient of the human body surface, and the action posture of the human body. Generally speaking, most women's swimsuits are well fitted. Therefore, the clothing pressure on the surface of the human body caused by the tension caused by the elongation and deformation of the clothing fabric is the most important factor affecting the pressure and comfort of the human body.
 
1.1 Influence of fabric properties of swimsuits on pressure comfort of clothing
When the human body is dressed, the material deforms and generates tension, which creates a sense of pressure. The physical properties of swimsuit fabrics related to pressure comfort include softness, smoothness, touch, biaxial stretch, elastic modulus, transverse stretch and bending properties of the fabric. Under the same conditions as other indexes, the greater the extensibility of the swimsuit fabric is, the less the stretch force the fabric is subjected to, and the less the pressure on the surface of the human body becomes.
 
The physical mechanism of clothing pressure is shown in Figure 1. The clothing pressure of the swimsuit can be calculated according to Euler's formula, and the clothing pressure is equal to the ratio of the elongation tension of the fabric to the curvature radius of the skin surface of the compressed part of the human body. Its formula is as follows:
 

Figure 1 The force diagram of the physical mechanism of clothing pressure
 

 
Among them, F is the clothing pressure. T is the fabric elongation tension. P is the curvature radius. y=f(x) is the rectangular coordinate equation of the human skin surface.
 
Since the elongation tension of the clothing is not easy to determine when the person is wearing it; the curvature radius of the skin is related to the person's gender, age and physical development. There is no unified standard, so this method can only roughly estimate the size of clothing pressure.
 
1.2 The influence of the human body's posture on the pressure comfort of clothing
In the process of dynamic contact between clothing and body parts caused by the movement of the wearer, the clothing conforms to the changes of the human body through relative slippage and deformation. During swimming, the whole body, such as the arms, shoulders, kidneys, and legs will exert force, and the elongation of the surface skin of different parts is different under different postures. Therefore, when the partial extensibility of the garment cannot meet the skin elongation of the relevant parts, pressure will be generated on these parts of the human body. The greater the elongation of the surface skin is, the greater the extensibility of the garment in the corresponding part becomes, thereby reducing the garment pressure at that part.