Run hard, run easy. That is about the idea with this workout.
Warm-up (5 minutes)
Start your run. Slow. Real slow.
Gradually increase intensity from slow to moderate pace. Run right into the main set.
Main Set (12 minutes)
Run 1 minute hard
Jog/walk 1 minute easy repeat x 6.
During each interval of hard running, ease into faster and faster gears. Don't start out at crazy speeds. Gradually work your legs out till you feel you can go full speed the last few intervals.
Cool down (3 minutes)