Seamless knitted sports bra design: A responsive system design exploration
The transition of sports bras’ uses, from an active lifestyle to resting activities, requires dynamic and adaptable comfort properties of the design, as well as adequate breast support, fit, and comfort. Thus, the two-fold purpose of this study was to: (a) analyze the use of current materials and processes in the product development process of seamless sports bras, via industry interview and observation, and (b) propose a design solution for a seamless sports bra that offers variable breast support during running versus resting activities.
Using a case study approach, an in-depth interview with a Santoni seamless knitting technician provided data that led to mapping out the design and product development processes used for prototyping seamless sports bras. A seamless business model for a sports bra was created, and relationships among the over-arching themes of planning, marketing, product development, innovation, and production, which emerged from the grounded theory analysis, were discussed. Moreover, a detailed Product Development framework and a Tech Pack model were created and used to communicate the new design for a responsive seamless sports bra. Interactions between design, prototyping and functionality and how these themes relate to the components of the tech pack were discussed.
At the materials level, a biomimetic system framework was used to identify solutions to responsive interactions within wool/Nylon/spandex blended yarns and various knitting structures when actuated by moisture. Twenty pattern designs were knitted on a Santoni circular knitting machine, using two different yarn combinations: (a) wool/spandex, and (b) wool/nylon/ spandex. Physical properties of the knit swatches were documented, as well as their thickness when dry versus three different moisture activation situations: (a) immediately after wetting, (b) after 30 minutes of air-drying, and (c) after 60 minutes of air-drying. Results showed that the Santoni circular knitting technology has capabilities to create a variety of texturally knit fabric designs that have a wide range of thicknesses, densities, and moisture responsiveness properties. Selections of knit patterns were made based on the textile testing results and used to design a responsive sports bra that incorporated female sweat maps and sports bra user needs. Sustainability considerations regarding the wet processing of the new responsive design were implemented, and the bra samples were not dyed, but only cold-washed and tumble-dried at low temperature.
Fifteen prototypes were developed via a Santoni circular seamless knitting machines and tested using human subjects and 3D body scanning technology. A convenience sample of fifteen semi-athlete female college students wore the new sports bra prototypes during three different moisture conditions: (a) before a run (dry), (b) after 30 minutes run on a treadmill (wet), and (c) after resting 30 minutes (starting to dry out). 3D body scans were collected in fully inhaled, as well as relaxed respiratory states after each condition. Questionnaires were used to evaluate comfort and responsiveness of the new design. The results revealed that the new responsive sports bra offers compression during the dry conditions, breathability and some level of breast support during running, and moisture management during the resting stage, all while offering high overall comfort and fabric softness. However, the length of the bra straps needs to be shortened, and the breast support during running needs improvement, therefore further design iterations are needed.
The proposed integrative approach to the sports bra design offers a new framing for the systematic design process of a sports bra as a functional design garment and fills knowledge gaps within the seamless knitting process using performance wool blend yarns. The new biomimetic-inspired sports bra solution has a potential for commercial applications that can offer women a responsive, adaptable sports bra, to encourage healthier lifestyles, as well as to accommodate for the athleisure trend.