The achilles tendon connects your calf muscles to your heel bone.  Tendonitis of this structure is extremely common.  Tendonitis simply refers to an irritation of the tendon and may be caused by repetitive strain or following an episode of acute injury or trauma to the region. 

Achilles tendonitis is characterised by pain felt at the back of the heel and running up towards the calf.  Normally the pain is worse when the athlete is cool and improves as they warm up.  It can often be painful on initial standing first thing in the morning or on getting up to stand having been sat down for a period.  Usually the first few steps are painful and it eases of as the athlete warms up within a few steps.

Achilles tendonitis is commonly found in sports that involve a lot of calf activity such as step aerobics, basketball, hockey, field sports and martial aarts.  If found and diagnosed early enough achilles tendonitis can be effectively treated with manual therapy and an eccentric rehabilitation programme and halt the development of achilles tendonsis; an extension of the condition in which the tendon has begun to degenerate.