Kevin Plank admittedly perspired a lot back in the early 1990s when he was a special teams player on the University of Maryland football team. After finishing his football career, Plank decided to find a solution to the problem. He spent the next several months going back and forth between his final classes as an undergraduate and a nearby tailor shop, where Plank tested fabrics for their sturdiness, water repellent qualities and comfort. The result was the first form-fitting, moisture wicking Under Armour shirts — the iconic product of what is now, a little more than a decade later, a billion dollar company. Under Armour still sells those shirts, but it has expanded into many corners of the athletic/casual wear market, from compression shorts to sports bras, innovative mouth guards and basketball shoes. During a recent presentation co-sponsored by Wharton Leadership Lectures and the Jay H.…