I've been generally fortunate in that I've had very few running injury issues. A bout of tendonitis and some ITB troubles and that's it. During the past three weeks I have run exclusively in my VFF's and am now experiencing some pains in my knees, achilles tendon, shins and just my feet in general. Here's my background: About one-and-a-half years ago I discovered the "concept" of barefoot running and bought my first pair of VFF's. Then someone gave me the book Chi Running which I've been using to develop proper form. I can only judge how I've been doing by how it feels to me and from some bad mirror angles at the gym, but it seems like I have learned to mostly do this well. The one thing I probably am worst at is the pelvic tilt. Last winter, following a Turkey Trot in the VFF's on frozen ground that made my feet hurt, I looked into some minimalist shoes and bought the Saucony Kinvara. Love it! I developed a pattern of running in my VFF's for my midweek training runs on the treadmill (usually about 4 miles each, twice a week) and using the Kinvaras for my weekend LSR outdoors. This system has worked just fine and I ran my first half marathon (in the Kinvaras) in April and then another one about six weeks later. So, a few weeks ago I decided that since I am no longer training for any more races this year, there was no reason that I shouldn't use my VFF's outside again. My last run in the Kinvaras was actually a "faux half marathon" on July 2 at 13.16 miles. Since then I've done my usual two treadmill runs plus a 6-miler on 7/10, 10-miler on 7/17 and 8-miles on 7/27 (yesterday). All in VFFs. Following each LSR, my knees are sore, my shins are slightly sore and yesterday was the first time with some tenderness in the achilles tendon. These symptoms are all helped by using a roller massage on my calves (which also feel tight, but that's not new). I don't run with an iPod because I'm REALLY trying to focus on my form which is why I "feel" that I'm mostly getting it right. This has become a frustration since I LOVE running in the VFF's. I think I may have an idea as to what part of my problem is and will be curious to see if it matches any responses from the resident docs. Thanks for your time and consideration!