Why Nike and Under Armour Are Spending Wildly to Watch Your Every Step

Sportswear outfitters like Under Armour and Nike look increasingly like tech companies, with apps and digital ecosystems that stretch far beyond their traditional fitting rooms and football deals. In the age of the Fitbit and Apple Watch, where web-connected fitness is increasingly de rigueur, the winner of the health-tracking arms race could potentially secure a gold mine from shoppers looking for the best way to break a sweat.