Let's suppose that you have decided to become a runner, and are looking at how to progress from being a walker to being a runner. The first part should not be neglected. Before heading off to becoming a runner, you should work on being a good walker. I'm not referring to speed for this, or for pretty much anything else I say. Rather, it is consistency that matters. Before starting on your running program, I think you should be comfortable with regular healthy walking. So you should be comfortable with going out 4-5 times per week and walking for 30 minutes before considering doing running.
Most people, runners perhaps more than most, like to ignore walking as a means of exercise, and as a requirement for fitness. The thing is, walking really is a good exercise in its own right. Depending on your current condition, it will get your pulse up nicely. If it does, then it is already giving you good aerobic exercise. Regardless of that, it is a weight-bearing exercise. If your aim is health, then these are your primary concerns. If walking gets your pulse up to the 65-75% level (see my heart rate calculator for some estimates of that), then it is sufficient. In fact, more than sufficient -- it is likely the safest, healthiest, way for you to get your pulse in to that aerobic training zone. Running means a big increase in your landing forces -- several times body weight. If your body hasn't yet adjusted to the forces involved in walking, running can be an invitation to injury.
Walk before you run is a very good training idea. If you're finding it somewhat embarassing, or whatever, to be working on your walking, feel free to supplement it with strength work, prehabilitation, flexibility work, or just telling yourself that you're not merely walking -- you're scoping out good routes to go running on. But walking really is the starting point. I'd post a progression if I knew of any. (Contributions?)
But then there's running.
Again, first be solid at the stage 0 of running -- be comfortable walking 30 minutes straight, 4 or more times per week. And establish this by actually going for walks of 30 minutes (or more) at least 4 times. And the day after the walks, still be comfortable and not have complaining muscles/joints.
Once you're to the point of being truly comfortable with a nice 30 minute walk (maybe a chance to say hi to the neighbors), then my idea is to include a bit of running in with your nice, healthy, 30 minute walk. Some people, particularly younger people, will be able to start later in the progression. That's ok. On the other hand, some people, particularly older or people more over their healthy weights, will want to start at stage one. That's fine too. The thing is, where you start doesn't matter in the long run. When I started, I started with 50 yards at a time. A few years later, I ran 50 km on trails. The starting point doesn't matter. Being consistent matters. Getting out for your next workout matters. Doing a lot in today's workout doesn't matter, and can actually be a bad idea. If it means you don't get out for your next workout, it's a bad idea.
The progression I give below is my own, so apply due grains of salt. It is derived from Jim Fixx's The complete Book of Running and the RRCA beginner programs. Fixx, I think, did better for starting from a true beginner -- someone who might find 30 seconds running (call it 50-100 yards/meters) a challenge. The RRCA, I think, does better for the later stages of moving up to the straight 30 minutes running. You'll find quite a different progression in Alberto Salazar's Guide To Running, which takes a full year to go from 30 minutes walking to 30 minutes running.
In terms of rate of progression of the stages, an attentive coach is a real help. If you don't have a coach, then you're your own coach. The thing your coach (you) need to look for is how comfortable your runner (yourself) is the day of and the day after each of the workouts. A healthy young person might start at stage 6-10, and then progress one stage per week. A not-so healthy not-so young person might take 2-3 weeks for each stage. Again, no problem. It is what it is. And regardless of what you do, the fact that you're doing something is a big plus to your health and fitness.
If you find that going one week per stage is too fast, then mix up the progression some. Let's say that you're 'stalling' at stage 2 (Hank?). We'll take that to mean that stage 2 is ok, maybe with some effort, but doing a full week of stage 3 is too much. One option is just repeat stage 2 until those runs become easy. If that's 4 weeks, so be it. Each of the 4 weeks you're doing something good for your health.
A different option, after you've established that 1 week at a given stage is no challenge, is to do one workout this week from the next stage. So do 2-3 of your workouts at stage 2, but one at stage 3. If your body is ok with this, then in the next week, do 2 workouts from stage 3. As best I've been able to establish from first hand experience and second hand (coaching), each of the stages I list is about as big a jump as the others. That may seem surprising, in that it suggests there's as big a jump in effort in adding 30 seconds running (from stages 1-2, or 2-3) as for adding 5 minutes (stages 9-10). But, honest, it squares with what I've experienced myself, and my runners have told me. (I also recently re-experienced the fact that from stages 10-11 is definitely as big as 11-12, and that's only 1 minute more running in the 30 minute workout!)
One last qualifier: Some people hit a plateau as they progress. It seems unpredictable where the plateau will be. But, for a week or three, it'll feel like the workouts aren't getting any easier. That's fine, just hang on whatever stage it is until they do start to ease up. If they're getting harder, drop back a level. The main thing, again, is to get out and do something. If you back off a level or two, that's fine. The converse will be the weeks when the next level is super easy. Now, if you're not getting out 3-4 times per week, you'll probably need to take more time on each level. 2 times is noticeably less effective than 3. On the other hand, 2 is far better than 1. And 1 is still tremendously better than 0.
Stage 0: Walk 30 minutes straight, 4 or more times per week
For the following, do 3-4 times per week, with 36-48 hours between workouts.
stage Run-walk Repetitions Running time
1 0:30-7:00 4 2:00
2 0:30-5:30 5 2:30
3 0:30-4:30 6 3:00
4 0:30-4:00 7 3:30
5 1 - 5 5 5:00
6 1:30-4:30 5 7:30
7a 1 - 2 10 10
b 2 - 4 5
8 2 - 3 6 12
9a 2:30-2:30 6 15
b 1 - 1 15
10a 2 - 1 10 20
b 4 - 2 5
11 4 - 1 6 24
12 5 - 1 5 25
13 9 - 1 3 27
14 14 - 1 2 28
15 30 minutes running