A rupture of the Achilles tendon is not an uncommon trauma in sporting activity and is quite dramatic when it occurs, as the calf muscles and the attached Achilles tendon play such an important function. It is more likely to occur in explosive activities like tennis. The real problem is that the achilles tendon and the two muscles connected to it cross two joints (the knee as well as the ankle) and if both joints are moving in opposite directions at the same time, especially if abruptly (as might happen in tennis), then the chance of something going wrong is fairly high.
The management of an achilles tendon rupture is a little controversial as there are two alternatives that almost all the research shows have much the same outcomes. One choice is conservative and the other is operative. The conservative choice is commonly putting the leg in cast which supports the foot pointing downwards slightly. Usually it takes up to six weeks to heel up and after the cast is taken away, there should be a slow and gentle return to exercise. Physical therapy is often used to help with that. The surgical option is to surgically sew the two ends of the tendon back together again, this is followed by a period of time in a cast that is shorter compared to the conservative choice, and will be followed by a similar steady and slow return to activity. When longer term results are evaluated the final result is typically about the same, however the surgical technique has the added risk of surgical or anaesthetic complications which the conservative approach doesn't have. The choice as to which approach is better is going to have to be one based mostly on the experiences of the doctor and the choices of the person with the rupture. There's a trend for competitive athletes to go along the operative option as it is considered that this may give a better short term outcome and get them back to the sports field a lot quicker.