First, my golden #1 most important rule of training: You have to enjoy the training because it can be as much as 99% of all of the running you do in preparation for a race. So whenever, I have to make a final decision on training, I will always think about that statement at the forefront. Because if you don't enjoy the training, then you won't stick with it.
The first thing I'd look at are my running shoes. Everyone is different when it comes to shoes. But I know when I first started on the slow run mindset, I had similar aches and pains trying to go slower. It didn't feel natural, and sometimes it felt like it hurt worse than just going a little faster. I ended up switching up my shoes to a more cushioned version (went from Saucony Ride to Saucony Triumph) and found a noticeable difference immediately. I've also tried to run fast in my Triumphs and I can't do it because it doesn't feel right. Every time I go out for a fast interval run, I do a warm-up and cool-down. For the fast runs, I use my Saucony Kinvara's which are my least cushioned shoe I use. Those warm-ups and cool-downs eat my legs up because of the Kinvaras. I do those same paces in Triumphs and no problem, but man is it hard to do them in the Kinvaras. So that's the first place I'd look when little aches and pains crop up from slow running.
Now for the sake of the thought process, let's say that changing the shoes doesn't help. The next question becomes -
19) If I told you to run as slow as you can, how fast would you be running? This would be at a pace where you're barely breathing differently than normal walking. It feels like you're barely trying.
You might recognize this question as one that I ask in my standard training plan list. The reason I ask this is because I want to get your unbiased opinion on how slow you think you can go. For 80-90% of the people I've worked with, the pace they tell me is the pace I schedule as the easy runs. Not because I altered the pace calculations, but because they usually fall in line together naturally. However, on occasion there are people whose answer is faster than the easy pace. For these people, I schedule the easy pace per the calculation and then wait and see. Some people adapt to the slower training pace in 2-3 weeks and others it might take as long as a year. But if things aren't working out with the slower pacing, and things don't feel right or it becomes not enjoyable then it's time to make a change.
So, we go back to question 19. How does that pace that you feel is the slowest you can run compare to the pace calculations given? For example,
This is a pace calculation. If the person came to me and said a 14:00 min/mile is too slow. The slowest I can comfortably run biomechanically is an 11:52 min/mile (HM Tempo). As a relative pace to their racing profile a HM Tempo run is 88-90% HR max or 84-90% VO2max. This is roughly an 84% effort. The goal for an easy run is about 65-78% HRmax or 59-74% VO2max which means if we did a sustained run at HM Tempo we wouldn't elicit the benefits of easy running. So to overcome this, I would say run the 11:52 min/mile which is the slowest pace you biomechanically feel comfortable at and add in walking breaks to ensure that the physiological stress you're putting on the body stays low. Running a HM Tempo is kept to about 30-60 minutes of continuous running, so an easy run at that pace has to be considerably broken up to maintain the "easy" designation. I am not well versed in run/walk, but this is how I would approach it.
The next question would be how fast do you walk? For the sake of this example, let's say this person walks a 17:00 min/mile (average human walk is about a 19 min/mile). The goal would be to find a run/walk ratio that keeps the run easy. Let's run through some different run/walk intervals and run the calculation -
A 4 min run and 30 sec walk (or 8:1 ratio) would be an average pace of 12:17 min/mile (there will be variability on a mile by mile basis purely from the standpoint of the intervals not ending at each mile marker). A 12:17 min/mile average pace is still too quick and more like a M Tempo run.
A 2 min run and 1 min walk (or 2:1 ratio) would be an average pace of 13:12 min/mile. A 13:12 min/mile average pace is still too quick and more like a long run
Although Galloway's recommendation I believe is even slower for a long run at 90-120 seconds slower than M Tempo, looks like his Magic Mile calculator says a 14:47 min/mile for someone with this race profile using a 15/30 run/walk ratio (or 1:2 ratio).
I'd probably settle on the 1:1 ratio like this one. It's 1 min run and 1 min walk, which comes out to an average pace of a 13:59 min/mile which is nicely in the easy category. Since this running pace is around this person's HM Tempo pace I'd venture to guess from a physiological standpoint this person could do 2 min run and 2 min walk or 4 min run and 4 min walk and still reap the benefits of the easy run.
At the end of the day, the true goal of the easy run is to increase the training load, induce active recovery, maintain a low to medium level of cumulative fatigue throughout the training cycle, and to induce the body into adapting and creating a better muscle structure (more and larger mitochondria and increased blood flow). So if we can hit this feeling of ending a run and it feeling super easy, then we're likely on track in gaining these benefits. With this coming the added benefit of always feeling comfortable biomechanically during the run without the feeling of causing new problems by going too slow.