Any garment that has made exclusively by design and fabric type to supportive a breast line for activity of any kind may consider as a Sports Bra. Which is why Sports Bras have come a long way since two jock straps were sewn together to form the first Sports Bra.
According to the varieties, bra has many divisions. For example, a Strapless Bra has no strap to hold from the shoulder but a tight grip around your chest-line and firm holding down to your breast to fix them. An Underwired Bra has the adjustable straps, two cups, a closure and two molded metal breast supports. In a soft-cup or triangle bra, there are same parts minus the metal breast boning.