A tear of the Achilles tendon is not an uncommon injury in sport and is quite dramatic if it occurs, since the calf muscles and the attached Achilles tendon play such an crucial function. It is more likely to occur in explosive activities like tennis. The real problem is that the achilles tendon and the two muscles attached to it cross two joints (the knee and the ankle) and if the two joints are moving in contrary directions at the same time, especially if abruptly (as might happen in tennis), then the chance of something failing is fairly high. The management of an achilles tendon rupture is a bit debatable because there are two alternatives that most of the research shows have quite similar outcomes. One option is conservative and the other is surgical. The conservative choice is usually placing the lower limb in cast which supports the foot pointing downwards slightly. It can take as much as six weeks to heel up and after the cast is removed, there should be a slow and gentle come back to physical activity. Physical rehabilitation is often used to help with this.
The operative choice is to surgically stitch the two edges of the ruptured tendon together again, this is followed by a period in a cast that is shorter than the conservative option, and will be followed by a similar steady and slow return to sport. If longer term outcomes are evaluated the final result is generally about the same, but the operative approach has the additional potential for surgical or anaesthetic complications that the conservative method doesn't have. The decision as to which method is better is going to have to be one based mostly on the experiences of the surgeon and the choices of the individual with the rupture. There's a tendency for competitive athletes to go along the operative pathway for an Achilles tendon rupture since it is believed that this may give a improved short term outcome and get them back to the sports field quicker.