After 10 minute warm up, you are going to run for 30 minutes as hard as you can for the entire 30 minutes. After starting the run, hit your 'Lap' button so you record the average HR over the last 20 minutes. This can be run on track or measured course (flat). Record the time and get a 10 minute cool down. Stretch when done and add in Core 1, 2 or 3.