Athleisure is still in the air. (And if you're resisting the coinage, give up, it's futile.) It's nothing new—Prada Sport was launched almost 15 years ago—but right now it's more pervasive than ever. At DKNY's Fall '15 presentation, no garment was safe from designer Garry Martin's infusion of gym-ready fabrics and details. Peacoats, blazers, and bombers all stretched enough to accommodate an all-out sprint—or perhaps a quick set of burpees—and came stuffed with down or with bonded mesh linings. "Guys don't want to keep buying the same staples," Martin said. "They've done it." Instead, he offered them those same staples with the comfort and versatility of activewear. Trousers in jersey or stretch wool were all cropped or styled with exaggerated turn-ups—perfect for showing off Huf's Thrasher socks. T-shirts were laser cut and bonded to be seamless, styled over turtlenecks, under blazers. Graphics came in three-dimensional form—either as bonded strips or fabric or heat-pressed forms in neoprene reminiscent of diamond plate steel. Layering is key to the DKNY look, and it helps to have fabrics that you can pile on without losing any mobility. Mastering the art of mixing activewear with street and formal clothes is an essential skill for guys who wish to be considered stylish. Martin proposed that we skip the mix and combine both sides so there's no distinction. The danger of this approach is, it's the intermingling, not the hybridization, that works best. Otherwise, you risk ending up with a tricky sartorial conundrum: functionality with no purpose.