Getting "jogging-fit" again

In the past I used to go in for moderate jogging. This came to a halt years ago when I contracted tendonitis in my right heel. This took a long time to heal based on using trainers with a heel wedge for normal daytime use, under the directions of a physio at the Freeman Hospital in Newcastle. I would like to hope that the recovery is by now complete. But whereas a teenager would have no hesitation in running to catch a bus, I feel that my calves have "forgotten" how to run (!). It is a fact that it is unusual to see the average mature adult in this part of the world "run" for whatever reason. Question: is there a way / are there exercises that I could use to "recondition" my calves without running the risk of re-inflaming my achilles tendon? Tks.