A tear of the Achilles tendon is not an uncommon problem in sport and can be very dramatic when it happens, as the calf muscles and the connected Achilles tendon play such an crucial function. It is more likely to occur in explosive activities such as tennis. The real issue is that the achilles tendon and the two muscles connected to it cross two joints (the knee and the ankle) and when both joints are moving in opposite directions simultaneously, particularly if abruptly (as might happen in tennis), then the likelihood of something failing is pretty high.
The treating of an achilles tendon rupture is a bit controversial with there being two options that almost all the research shows have got quite similar outcomes. One choice is conservative and the other is surgical. The conservative option is commonly putting the lower limb in cast which holds the foot pointing downwards slightly. It can take up to six weeks to heel up and after the cast is removed, there should be a slow and gentle resumption of exercise. Physical therapy is usually used to assist with that. The surgical choice is to surgically sew the two edges of the tendon back together, this is followed by a period in a cast which is shorter compared to the conservative option, and is followed by a similar steady and slow resumption of sport. When longer term results are evaluated the final outcome is usually about the same, but the operative procedure has the added chance of surgical or anaesthetic complications which the conservative strategy doesn't have. The choice as to which approach is better will have to be one based on the experiences of the doctor and the choices of the person with the rupture. There is a trend for competitive athletes to go down the operative pathway for an achilles tendon rupture as it is thought that this does give a better short term outcome and get them back to the sports field faster.