Comfort During Motion: Analyzing the Pressure Profile of Auxetic Bra Pads

Auxetic structures, characterized by a negative Poisson's ratio and unique form-fitting deformation, are adopted for designing a bra pad that would facilitate bras with a flexible and adaptive fit. This study compares the pressure distribution between auxetic and traditional molded bra pads, highlighting the advantages of auxetic materials in applying uniform pressure and addressing health concerns. Seven athletic female participants with a bra size of 75B comprise the study sample. Anthropometric data of naked breasts are collected by using three-dimensional (3D) scanning to obtain the underbust and full bust dimensions in the standing and leaning forward positions, while the pressure distribution is measured with the Novel Pliance^® pressure measurement system in three poses: standing, static cycling, and dynamic cycling. The results show that the auxetic designs of bra pads consistently apply a more uniform pressure distribution compared to traditional foam pads, with mean pressures of 2.92 kPa for auxetic pads compared to 4.81 kPa for traditional foam pads during static cycling. Moreover, auxetic pads reduced maximum pressure by 25% compared to molded cups, and spatial variability was halved (SD 0.85 kPa vs. 1.70 kPa). Notably, at the bra neckline, auxetic pads exhibit increased pressure as the body leans forward, demonstrating their ability to adapt to changing breast shapes while maintaining adequate bra-breast contact. In contrast, in the lower breast area, the auxetic pads show a decrease in pressure, which indicates their capacity to accommodate variations in breast girth or volume without exerting excessive force. These findings highlight the superior adaptability and wear comfort provided by an auxetic structure, which shows its potential to address the dynamic support needs of active women. Overall, the auxetic designs of a bra pad in this study represent a significant advancement in sports bra technology and offer a promising alternative to traditional molded cups in activewear design.