Each week should have a longer run, which comprises no more than 35 to 40 percent of the total week's volume, as well as one moderate marathon-paced session for anaerobic threshold stimulus. For economy purposes, I recommend gear (or pace) changing within the long run: surge for one minute every six to eight minutes, and finish one to two additional runs during the week with six to eight x 100-meter post-run strides (or accelerations) for rotation.
Below is a sample week during this period for someone who is beginning his or her training in sound shape, and running roughly 50 to 55 miles a week.
Sample Week 1 of the Marathon Crash Course
Sunday Long Run: 18 to 20 miles with the final 8 to 9 miles run moderately. In addition, throw in a one-minute pick-up every seven to eight minutes over the final 80:00 of the run. Conclude run with 6 x 100m strides for economy.
Monday: Rest day—optional non-running exercise such as swimming or pool running.
More: The Importance of Rest for Runners
Tuesday: Easy 6 miles at conversational pace.
Wednesday: 8 to 9 miles with 10 to 12 x moderate three-minute pick-ups in the middle of the run at 10K or half-marathon effort with two minutes of easy jogging between each pick-up.
Thursday: 7 to 8 miles relaxed running (optional non-run workout as second session of the day).
Friday: 6 miles "as you feel;" finish with 6 x 100m accelerations.
Saturday: Athlete's choice day, but keep the run effort controlled.
As you can see, we have a long run in play as well as some moderate work to begin improving tempo-based strength. Accelerations as well as the long-run surges will improve economy. For improved aerobic conditioning, there is the option for a couple of additional non-running workouts such as deep-water pool running or swimming.
More: 7 Cross-Training Exercises for Runners
Increasing volume is normally an important part of marathon training (using the first four to five weeks to ramp up to goal mileage); however, during the crash-course plan, a runner needs to be jumping on his or her targeted marathon volume fairly quickly—in the first one to two weeks.
Sample Weeks 2 to 3 of the Marathon Crash Course
Sunday Long Run: 18 to 22 miles easily with moderate surges over the last 90 minutes of 1:00 – 1:00 – 2:00 – 1:00 – 3:00 – 1:00 – 5:00 – 1:00 – 6:00 – 1:00. Take seven to eight minutes between each surge to get back to a comfortable training rhythm. Pick-ups should be assertive but only so fast, as you should be able to return to your pre-surge tempo. Run controlled for seven to eight minutes over the final 60 to 65 minutes. Conclude run with 6 x 100m strides for economy. Be certain to practice fluid and energy intake during your long runs. Take six to eight ounces of fluid every 30 to 35 minutes, and ideally 100 to 120 calories of energy intake within the same period.