Tune Runner is a music-fitness iPhone app with a distinct iOS7 look. Tune Runner detects your running pace and builds a playlist of songs with a matching tempo.
As long as you run at a pace close to the song's tempo, the song will keep playing, encouraging you to keep up. If you run faster or slow down, Tune Runner will auto-adjust. A visual indication shows if you're drifting from the song's beats.
If you're running at a steady pace but want the music to drive you to run faster you can tap the "faster" button, and a new playlist will be built for the faster pace. Conversely you can force a slower pace to cool down.
Tune Runner uses the EchoNest search API to find songs that match your pace, then streams music and cover art from Rdio (an Rdio account is required to hear full songs instead of 30 second previews).
Tune Runner doesn't currently support music genre or playlist selection, but the playlist is optimized for energetic, upbeat songs.