Core Exercising My Way Back In

After missing half of June, all of July, and most of August for lots of summer related issues, I've started back running and bicycling.  Immediately, my left hip and glutes were very tight!  So tight that after an 8-mile run in early August, I could barely walk.  So I've taken to heart Eladio's simple core exercises and stretches that hit the mid-body and am slowly beginning to build my base.  Ran 6 last Saturday and 6 this Saturday with Runner's Edge and felt much better this week.  Biked 33 miles in the Bike for the Brain ride last Monday (Laobr Day) and realized I need to log more bike rides to be comfortable on our Katy ride.  Lastly, I attended Eladio's seminar with a sports therapist 2 weeks ago and am trying to remake my stride to the forefoot strike featured in the book Born to Run.   My goal is to completely rebuild my stride to proper running form and build my mileage base this fall, with core exercises a  part of my daily routine.  I'm also mixing in a half mile for now of barefoot running on my gym's indoor track 3 times a week to help me relearn my stride.  I'll slowly build that base and also move to shoes that have less heel to toe vertical lift over time till I get to flat shoes (my current Brookes have a 12 mm vertical lift, which is common.  Minimalist shoes have 0 mm vertical life).  It's my fall makeover, and if I can pull it off, it should set me up well for the long haul!