*Disclaimer: I am in no way discrediting or inferring that Jeff Galloway's Dumbo training plan is incorrect or wrong. These are merely my thoughts and opinions.*
I'll just jump right into the training schedule part. (If you're interested in my thoughts on the introduction part, continue reading below.)
Galloway sticks to a walk/run method which gets you across the finish line with very little risk of injury. For our analysis, let's say that you follow a run/walk pace of 10 mins/mile (run 4 minutes and walk 1). The Tuesday/Thursday maintenance runs are almost all 30 minutes, with an increase to 30-45 mins seen for 3 weeks (Thursdays on weeks 13, 15, and 17). That would give you ~3 mile runs, which is a good distance, but not too strenuous.
My analysis really has to do with the long run mileage.
Weeks 1-6: The long run starts at 3 miles, jumping up and down until Week 6's 6.5 mile run. There is almost two weeks of running ~3 miles and then a big jump to long run of 6.5 miles. Some may prefer a more gradual increase from the previous week.
Weeks 7-12: This is when the back to back runs start coming into play. The back to back runs are scheduled every other week. The shorter 10k prep run increases 1 mile, while the half marathon prep run increases 1.5 miles. Sounds good, until you look at the long runs on the in between weeks- only 3-4 miles. You're doubling, almost tripling, the previous week's long run, not to mention it's the second part of the back to back run.
Weeks 13-18: The mileage keeps increasing at the same pace (1 mile added to the 10k run, 1.5 miles added to the half run). By Week 16, at 2 weeks before the race, you will have gone your furthest distance at 5 miles on Saturday and 14 miles on Sunday. Personally, I would go 6 miles on Saturday and only 13.1 on Sunday. At the end of a long run, you're tired and your form isn't as good, opening up the possibility of injury. Why risk it?
Week 19: Following up your race with some light running is always a good idea.
For some comparison, here is my Dumbo plan.
I actually took a lot of the back to back run scheduling from Galloway's Goofy training (his is every 3 weeks, mine is 4). His Goofy training is a lot longer (due to running a half and then a full the next day), but I feel the increase in mileage is more gradual. I kept my long runs pretty long, too. I need to keep the mileage up or it's too hard for me to increase it again. I also run 4 days/week, instead of Galloway's 3.
Here's the introduction to the official training plan, along with my thoughts on it.
He mentions that this is for experienced runners (more than 6 months), but I would argue that a non-runner would be able to follow this as well.
He goes into more depth about the walk/run method.
Galloway provides a break down of the walk/run for difference pace times. For a 9min/mile pace (giving you a sub-2hr half marathon finish), you would run 4 minutes and walk 1. He also touches on cross training and while I agree that it may not directly affect your running, it can help improve endurance.
This is where he explains the "Magic Mile". Essentially the magic mile gives you an idea of the pace to expect on race day. It's an interesting idea and would be worth checking out.
Have you used a Galloway plan? How do you like the walk/run method? What do you think about Galloway's Dumbo plan?