When Adidas bought Runtastic for $240 million in 2015, the fitness giant was pretty obviously playing catchup. The company had just watched Under Armour, a relative upstart in the sports apparel world, spend $710 million on three of the biggest fitness apps on the market: MapMyRun, MapMyFitness, and Endomondo. Less than a year later, Japanese shoe brand ASICS would snap up Runkeeper for $85...
