Mike, I think you're wise to be concerned and conservative.  In some cases the thickening of the tendon is indeed indicative of tendinopathy (usually tendinosis).  The form of exercise that seems (at least according to research) to be most helpful in stimulating collagen reformation is eccentric-type exercises.  In other words the lowering phase of your calf raises.   Use of a heel lift usually helps to relieve some of the chronic load on the tendon, but it can lead to a shortening of the muscle/tendon unit so you don't want to use the lift for long.  Have you had a gait analysis done to see if there is something biomechanical that's contributing to this? 

Hope this helps, Janet

Treat the cause, not just the symptoms... http://www.runningstrong.com

Hi Mike,

I have been fighting a bad Achilles heal for a while.  Seeing a DR and getting an MRI is a good first step but you seem to have a classic case.  Ibuprofen (after runs), icing after runs, heating pads at night/or when ankle is NOT already inflammed from running, vibration (use the same as heat), heal lifts, taping your ankles (very useful for shorter runs...say less than 5 miles but loose support on longer runs), and Achilles tendon braces (more cumbersome and less comfortable than taping but with velcro adjustable straps so that over a long run you can stop and adjust the tension relief on the tendon) can help you run through minor pain.  I use a combination of all of these.  If you DO use a lift...be sure to use it in both shoes so you don't throw off your bio-mechanics and make things worse. 

If you had caught this BEFORE you developed a bump (which is most likely a calcium deposit) giving your ankle a rest could have made the difference.  However, once the calcium has built up it is difficult for it to be broken down.  Surgery or ultrasonic treatment may eventually but your only long term option.  Surgery can take a year or more to recover from a runners perspective.  Only your Dr. can really say how far advanced your calcium deposit is.  Very likely, you might have had a tendon tear early on that started all this and ran through it...the pain is not really that high on a typical run because the tendon "warms up" even though the pain can be quite high in the morning or decending a flight of stairs after sitting around the house.

One more piece of advice...try to avoid running on your toes or barefoot running with an achilles problem...this really strains the tendons.

Please post anything useful you find..you are certainly not the only runner with this problem.