This is inflammation in the bursa (fluid filled sac) behind the Achilles tendon where it joins on to the heel bone (calcaneus). The bursa usually acts to prevent rubbing of the tendon on the bone, but when it gets irritated, usually due to excessive friction, it becomes inflamed. Footwear which is excessively tight across the back of the heel presses on the Achilles tendon which in turn irritates the bursa. Biomechanical problems may also be an underlying cause.
You will feel a pain at the back of the heel which may be associated with swelling. There may be a very specific area which is tender when you press.
If you think you have this condition it is well worth getting it checked out by Mr Willis-Owen. In the mean time you should avoid any aggravating activities which may prolong the problem. The first thing to do is to reduce the problem activities, and start gently massaging the area. Anti-inflammatories and ice are helpful after exercise.
Treatment involves first confirming the diagnosis then establishing the cause. An x-ray can be useful to assess whether there are parts of the calcaneus contributing to the problem. Treatment options may include anti-inflammatories, or very careful injections. Very rarely surgery is required. Once you are recovered it is important to address any biomechanical problems, or other underlying factors in order to prevent recurrence.