Injuries are inherent to sports. In case of an injury, it is important to make sure that the injured amateur of athlete doesn't lose his or her stamina.
Training at altitude is ideal in that case, because when training at altitude at a lower intensity than normal, the training response is much bigger than at sea level. In a period of rehabilitation, high altitude training is the optimal solution. Training can be done at home by sleeping at altitude in an altitude tent or at the gym inside a high altitude training room.