As if the post-workout selfie weren’t enough of a humble brag, now the fashion and publishing set can exercise in exclusivity. Nike has one-upped its pedigree on Instagram with a new fitness studio enigmatically known only by its address: 45 Grand. Since mid-April, a select few, mainly editors and social media mavens, have been congregating in SoHo on Tuesdays and Thursdays for invite-only yoga, barre, high-intensity training and Nike+ Run Club jogs, all in the privacy of a state-of-the-art classroom decked out in Nike swag. Heaven forbid you should be caught working out with the plebes at New York Sports Club. The venue opened last fall to showcase the brand’s women’s collection, and similar to a fashion showroom, displays new products and services on top of offering group instruction. As a perk, guests are greeted by lockers featuring digital screens with each of their names, which look especially enviable with a Valencia filter.