Best for: Racing your buddy
Turn your usual loop into a virtual race by using the Yog app (free; iTunes) to set a start time and distance with a friend or to hook up with other "yoggers." An onscreen avatar shows how far along your pal is, and a recording announces, "Congrats, you're in the lead!" when you dust her.
Best for: Firing you up
The Songza app (free; iTunes, Google Play, and Amazon) has tons of tunes to suit you. And now FITNESS has teamed up with Songza to create thumping playlists for any cardio. Get the skinny at fitnessmagazine.com/songzarun.
Best for: Keeping you honest
If you didn't post it, it never happened, right? The Cody Digital Exercise Journal (free; iTunes) is like Facebook for fitness diehards: Upload pics from your run and mileage totals as you brag to, er, link with