Jumper's knee or patellar tendinopathy is a clinical diagnosis manifested by the appearance of pain in the front of the knee, most often at the tip of the patella, that is, at the starting point of the patellar ligament. Jumper's knee is caused by eccentric contractions that overcome the force of gravity. The quadriceps is the main muscle that overcomes this force. Jumper's knee is a trauma that is constantly repeated and thereby overcomes the ability of tissue repair. It can occur in athletes who have just started sports activities and in professional athletes who have been training for many years, so the period during which athletes play sports has no significant influence on the onset of the syndrome. The clinical picture is characterized by a feeling of deep and sharp pain and sensitivity of the knees, and there may also be reduced functional ability of the affected lower limb. In the beginning, the pain occurs during active and passive stretching of the upper leg muscles, later it can also occur during muscle contraction or during contraction against resistance. At a later stage, the pain may suddenly appear at rest, and occasionally the pain spreads along the upper leg muscles. Diagnostics first starts with a conversation and taking an anamnesis, in this case various questionnaires can also help. The most common form of treatment is conservative or non-operative treatment, but in some rare cases surgical treatment is the only solution. Conservative treatment begins with familiarizing the athlete with the problem, the method and duration of rehabilitation. It is important to start as soon as possible, that is, as soon as the first symptoms appear. Some other forms of treatment that can be applied are massages, electrotherapy, cryotherapy, ultrasound or laser therapy. With regard to the localization and stage of the jumping knee, therapy should be individually adapted to the patient. Kinesitherapy as a type of therapy uses movement in the treatment and rehabilitation of diseases and injuries. Of the exercises, eccentric and concentric exercises are used, but eccentric exercises are used more often. Also, with the rehabilitation of the jumper's knee, great persistence is required because the process is not short-term, but the exercises should be carried out over several months. Rehabilitations with unrealistic time frames, especially for professional athletes for whom a quick return to sports is very important, cause great difficulties in the successful rehabilitation process. Due to the disappearance of pain, patients stop the therapy prematurely, and this can lead to the reappearance of jumping knee.