Under Armour reported second quarter revenues that increased 9% on a year earlier, but the management cut guidance for the full year. That reflected a weaker outlook for the North American market, and resulted in a 10% drop in the firm’s stock price. U.S. imports of Under Armour products in June and July – the first two months of inventory for the third quarter – fell 12% on a year earlier. That left it well behind Nike, which recently returned to growth, Adidas and Skechers which all increased their shipments in the same period.