Music has a positive impact on your running speed. Runner tracks this by logging your pace per song as you run and then it lets you create a custom length playlist of your fastest songs.

-Run smarter.
Sort playlists by your pace per song. Match your running style: fastest song at the middle for long runs or at the end for short runs.

-Run faster.
Create a custom length playlist of your fastest songs.
Nothing will slow you down.
At least not your music.

-Track your speed.
Time elapsed, distance and run pace read to you every 1/2 mile.

-Smart controls.
Select a playlist and put your phone away.
Start, pause and resume your run from your headphone's button.
Double click to skip a song.

-Use your favorite songs.
Runner uses the playlists you already have on your device.

Note: Continued use of GPS running in the background can dramatically decrease battery life.