RunKeeper adds that iPhone 5s special sauce to its running app

If you thought that Nike+ Moves was the only fitness app to quickly latch on to Apple's new M7 co-processor, think again. RunKeeper has announced that the latest update to its iOS app will now automatically track periods of activity lasting longer than 15 minutes and will also track your cadence -- letting you analyze that statistic with the same level of obsessive detail as you do your pace and elevation. If you own an iPhone that isn't a 5s, the company is throwing a bone your way too, letting you prove how grueling your morning run is by sharing route details to other users over AirDrop -- as if those incredible calf muscles weren't evidence enough.