Chondromalacia patellae, also known as “runner's knee” is an injury caused by its overuse. It also means the softening of cartilage of patella. The knee is the largest joint of the human body. It's made of the most complicated material so its the joint that is most often injured. Ossification of patella begins in the third year of life from one or more centers of ossification. The shape of the patella is formed during life between the two tendon levers, tendons of m. quadricep and the patellar tie. To plan preventive measures, apart from that we need to get information on why an athlete in a particular situation risks getting injured, it is even more important to know how a certain injury occurs. Runner's knee can cause hormonal disorders, cartilage eating disorders, changes in the sliding path of the patel, disorders in the position of the patel. Sports injuries, their location and severity are changed due to the biomechanical characteristics of a particular sport, age and gender of athletes and the conditions in which sports activities take place. The principle of treatment is to calm the local inflammatory process, enhancing tissue healing and rehabilitation of the affected extremity so that a person can achieve full sports activity as soon as possible. Rehabilitation is a complex process of training, to the fullest possible extent, for the more normal life and work of people with injuries and their return to sports activities. Medical rehabilitation is made up of medical treatment, special care, physical therapies, kinesitherapy, working therapy, aids and education.