Buy In: 1) Take your shoes off. Tabata Downdog progression.2) Stretch the tops of your feet by laying the top side of your toes against the floor and pointing your feet actively. This may be intense. Work on this until it becomes considerably less intense. 3) Mobilize. You're going running.
Copied and pasted from CrossFit.com:
5 rounds, each for time, of:
Run 800 meters
Rest 3 minutes