This session starts with a 20-minute jog and 3 gradual 15-second accelerations as a warm-up.
You're then going to run at almost max pace for 45 seconds, followed by a very slow jog for 45 seconds. Do this 10 times in total.
Finish the session with a 10-minute warm-down (at no more than 65% of your maximum heart rate) to relax your muscles and gradually lower your pulse.
You'll recover more quickly and your body will cope better with the next session.