MANY interesting points in here. A little history on me: I was a basketball player in highschool and a rugby player in college. Neither of which were "endurance" events and I never enjoyed running, though I have always considered myself athletic. The best 1 mi. I had ever ran prior to crossfit was 6:27 my freshman year in college, and I was spent for two days after that. I now attend chiropractic college and have learned quite a bit about the biomechanics of walking and running, and thru that time have changed and modified my running style. I am very conscious of my foot-strike and posture while running, so as to optimize my movements. It has helped ten-fold in relieving pain associated with long runs (just recently finished my first 10-mile run with little "effort") The other thing I learned in chiropractic school was the importance of the musculature that supports the foot. When running on any surface, your muscles of your lower leg insert into the arches in your foot and act as a natural shock absorber and cradle the foot to land as gracefully with each stride as possible. One of my professors has a paper on some simple drills to strengthen those muscles. I do them at least four times a week and have not had ANY foot or shin pain while increasing my milage (I had a small amount in the beginning before the muscles were strong enough, and the pain did not start until I felt lower leg fatigue set in). Here is the link to the paper on the foot drills: http://wellness.ndsu.nodak.edu/fitne...footDrills.pdf
(work/family safe link). I recommend doing these religiously while focusing on strengthening those muscles. Your long runs should end as soon as you feel those muscles fatigue, as you will then have a longer recovery period due to the strain you'll place on the joints of your feet, ankles, knees, hips, and low back. Finally, I spoke earlier of my best mile ever. After doing the WOD's for a little over a month and with no running during that time, I ran a 5k in just under 20 minutes, then turned around and jogged home. The metcon, or cardio, you can receive thru the WOD's GREATLY affects ALL aspects of endurance training. When folks talk about your interval runs, this is for the same aspects that the "girls" and similar workouts do, without the impact that pavement running can have on your body. MY recommendation to you, as someone who is an avid crossfitter for a little over two months and is training for their first half ironman this summer, is to stick to the WOD's (scale as needed based on strength and fitness level, push yourself to a point short of injury) and do a long-run once a week, very slowly increasing your distance. Use the long runs to work on proper running gait (if you would like some advice there, I can offer it) and slowly increase the milage. I am currently dating a division 1 distance runner (have turned her into a crossfitter as well and she loves it) and I'll see what she suggests for milage increases. I hope this helps, and keep us all posted.