I find that when I am running at race or tempo pace (between 5:30/mile and 7:00/mile) I find it easy to engage into good form and settle into comfortable running. However when I slow it down towards easy run pace (circa 8:00/mile) I find it hard to keep up good form. I tend to find myself slouching and I generally feel uncomfortable, tense and end up with lower back pain and the run ends up feeling laborious rather than easy. If I consciously make an effort to run with good form I just end up speeding up and ending up back at tempo pace which completely defeats the point of an easy run. Does anyone have any tips on how I can keep good form and still maintain easy run pace? Are the any techniques I could adopt etc?
I try to shorten my stride when consciously trying to slow down. While my paces aren't nearly at your level (my strenuous effort is near your easy pace!), I do find that it's far too easy to speed up before I want to. With a deliberately shorter stride, the only way I can maintain the same faster pace is to speed up my footfalls, which feels more awkward.
I also try to keep my hands and arms down and loose. I focus vividly on keeping my shoulders relaxed (mostly because during a HM last year, when I passed a friend on the course, she yelled at me to relax my shoulders and drop my arms because I was apparently too tense and clenched).
The best thing you want to do is have good form, that way you are not hurting yourself in anyway. Thats the first and foremost thing. The second would that good form means you are working the muscles well and optimally. So try keep you form at its best as that will work out better for you in any run.
What you could do is try do technique (form) exercises that could help you get the movement right at very slow place, and then getting it more intense as you go along, hopefully to the point where it becomes second nature.
I remember learning to run, and we had to keep our arms at about 90 degrees locked, straight back, head up right, and strive for high knee (but not too high).