The countdown begins. There are 12 weeks between now and your half marathon. In the Advanced program, Monday is always a day of comparative rest to help you recuperate from hard weekends. Comparative rest means you run 3 miles at an easy pace. What is easy? You need to make that determination yourself, and the exact pace may vary from week to week. I recommend that you also consider using this day to do some stretching and strength training. You will have more time to do this on Mondays (and Wednesdays) than you will on Tuesdays or Thursdays, which are speedwork days.
6 x Hill. Find a hill 200-400 meters long, moderate incline. Run it a half dozen times, jogging back down between. This workout should be equal in difficulty to if you ran 6 x 400 on a track. For the first half of the program, you will alternate between running hills and running 400s. Jog a mile or two to warm-up before hitting the hills. Afterwards, do a mile or so of jogging to cool down. And don't forget to stretch!
Three miles run at an easy pace, similar to Monday's workout. Speed doesn't matter; distance does. Three miles will be your typical Wednesday workout, however, as the program continues and mileage builds, I will offer you the option of taking a complete rest on either Monday or Wednesday. Note that in the duration of all the workouts in this program, I assume that you train at an average pace of 8:00 per mile. If you run faster or slower, you can adjust that time estimate accordingly.
Forty-minute tempo run. Run the first 10-15 minutes easy, pick it up to near 10-K pace in the middle, then ease back by running the last 5-10 minutes easy. To do this workout properly, you should both accelerate and decelerate gradually, meaning you will only be at peak speed for a few minutes two thirds of the way into the run. A tempo run can be either your toughest workout of the week or your most enjoyable--and sometimes it can be both.
Three miles at an easy pace. As we progress through the 12-week program, you will be asked to run some of these Saturday workouts at your half-marathon race pace. If you want to do your long runs on Saturdays rather than Sundays, simply flip-flop the two workouts.
Run 90 minutes, using a 3/1 pattern. Run the first three-fourths of the distance (or about 65-70 minutes) at a comfortable pace, then speed up during the last one-quarter of the distance (20-25 minutes) to near your half-marathon race pace. Not at that pace, near that pace. Don't overdo it, but I do want you to get used to running fast when you are fatigued. Please note that I have prescribed the Sunday workouts in time rather than in distance. That's because you are an Advanced runner for whom running plus or minus 13 miles offers little extra stress. Think less of how many miles you run and more on how well you run those miles.
Monday is the day you kick back after your hard work over the weekend and run an easy 3-miler. It may not seem that you need much rest in this second week of your 12-week program, but as the mileage continues to mount, you will appreciate this easy day. Even though you do only a few miles today, Monday is a good day for some stretching and strength training. If you feel you need more rest on this or any other Mondays, take a full day off.