Since this came up again, I'll share my experience as this is my first post ever on this forum. Although mine is insertional achilles tendonitis, hopefully it will still help. Here's the story: I was deployed as a contractor and spent a year in the middle east running my ass off on treadmills and really flat surfaces in Saucony Kinvaras and theen immediately sitting in a chair in a converted warehouse for 60 hours a week. I trained harder and harder and got slower and slower. Then one day on an uphill treadmill workout I just felt something go in my left achilles insertion and stupidly finished the workout. That was April 2014. Throughout the rest of the year I came back and spent it on and off running, not doing workouts, losing fitness. Long story short, I actually recovered from it after doing the things I'll explain below and then re-injured it and got it again. So here goes everything I've learned and will recommend, in list format...
Active Treatments:
-Go to a Graston/ART specialist and have Graston done. It takes like 6-8 weeks of sessions 1-2 times per week but it works.
-Someone else mentioned it but biomechanics are huge, go get a gait analysis done. As someone mentioned again shoot for 180 steps per minute and shorten your stride.
-I never had success with PT, my Graston guy is a Chiropractor, also of note I never actually had success with doing heel drops/toe raises but to each their own.
Other stuff that is really important:
-Footwear. Can we just stop with the minimalist thing? I mentioned earlier, I thought I was fully better after a while so I threw my Kinvaras back on and hit a track workout. Bang. Back to square one. I understand it works for some people but I've given up light weight minimal shoes. I run any hard workouts and quality in Mizuno wave inspires (huge heel/toe ratio, 13m or something) and I run easy runs in...I'm finally ok saying this...Hokas. I could no longer ignore stories that they fix injuries and grabbed a pair and honestly, it works. I actually bought a pair for my Dad who isn't even a runner and my Uncle. I'm fully on board the Hoka bandwagon.
-I have certain rules now, no more track workouts, maybe ever, definately no more Kinvaras ever. You can still do 200s, 5k repeats, 800s, whatever on flat roads or dirt paths or treadmills.
-Stretch after every run for just 5 or 10 minutes, every run, for the rest of your life, just do it.
-Warm up slow, maybe do a few pre run glute exercises to activate but first mile, especially in the morning should be pretty slow.
-Get a massage regularly, once a month or so.
-Run varied routes up and down hills and on hilly terrain. I think what did me in was all the flat running for a whole year and no downhills, downhills are really eccentric.
Now, my final note, find your nearest mountain and hike it. Seriously. Then do it again the next day. As a matter of fact do it as much as possible, do it until it not only fixes your achilles but activates your glutes and quads and hamstrings and all those other fantastic muscles that need to work so your achilles doesn't have to do as much. Then start jogging the mountain. Once it is healed run as much as possible on soft surfaces even if it is inconvenient. Run trails a lot and do hard workouts on a soft flat surface or treadmill.
Even now I hesitate to call myself fully recovered but I'm running more mileage injury free than ever before.
Thats my 2 cents, its long but hopefully it helps someone! Good luck!