TrailMix Music Player (iOS) app for FREE

STEP TO THE BEAT while you walk or run – just pick a song and TrailMix changes its tempo to match your pace, even as you speed up or slow down! When you play a song TrailMix digitally "listens" along with you and locates the beats in just a few seconds. Then, TrailMix detects your steps and makes the song faster or slower to match your pace, adjusting in an instant when you change speed.+