While many sports bras are constructed without wires, there is a good selection of sports bras that do have underwires. Made of flexible plastic or coated metal, underwires provide great support, which is crucial in sports bras. Larger-breasted women, in particular, will benefit from a full-coverage underwire sports bra. Many underwire sports bras encase and pad the underwires for additional comfort. In larger sizes, underwire bras may have a wider curvature for a comfortable supportive fit.
Underwire sports bras will also have most of the same construction techniques as soft-cup sports bras, including leotard back, compression and/or encapsulation, wider straps and a breathable moisture-wicking material. A sports bra should feel somewhat snug to minimize bounce and provide support.