This is an excerpt from Daniels' Running Formula-4th Edition by Jack Tupper Daniels.
I have designed a workout plan for the variety of race distances covered in this chapter that is somewhat different from what I usually suggest, and I have called this my alien training plan. This plan assumes the runner who will follow it has been running regularly for a while. It also assumes the runner is familiar with the types of training I offer (E, L, M, T, I, H, and R) and with how to adjust the speeds (determined by VDOT values) and amounts of these types of training, as outlined in chapter 4. This understanding will allow the runner to determine the details of each workout presented. In other words, if I say that a particular workout is to be an R session, the runner knows the speed, recovery, and the maximum amount of running to do at R pace and can select a session from those presented in chapter 4. I suggest a type of workout and the runner determines the details of that training session. You will notice that the alien program does not go through a series of training phases; rather, it presents a series of workouts that are repeated every 2 weeks.
After trying alien training for a few weeks, you might find that it works well for you and may even be a good program to follow when training for a race shorter than 15K or longer than 30K. In fact, I think it may be a good marathon-training program for some runners (see my 18-week marathon training program for novices in table 16.2).
In the alien program shown in table 15.1, I list 7 training days for the week (day 1 through day 7), and the 2-week schedule presented is repeated as many times as desired. You decide which day of any week best suits your schedule. I usually think of Sunday as being day 1, which is Q1 of each week, with Q2 on Tuesday and Q3 on Friday, but your schedule may dictate different days for you. All I suggest is that you keep Q1, Q2, and Q3 in the order they are written and schedule E days between the Q sessions. Notice that I have suggested adding strides (ST) to a couple of E days each week. Do what you feel is adequate for the warm-up and cool-down associated with each Q session. When you are within a week of a race, switch to the prerace week. Prerace weeks and the following recovery period are the only time that the program is varied. Therefore, following any race, take 1 E day of running for every 3K of race distance; for example, if a race was 15K, take 5 E days for recovery before returning to the alien program and 7 E days following a half marathon.