Age 18-35 years old (the chosen age range will minimize chances of other conditions causing anterior knee pain such as osteoarthritis and osteochondrotic diseases like Sinding-Larsen-Johansson syndrome and Osgood-Schlatter disease) History of knee pain in patellar tendon or its patellar or tibial insertion in association with training and competition Playing sports for at least 3 times a week Palpation tenderness to the corresponding painful area On ultrasound, there needs to be a fusiform tendon thickening and/or decreased tendons structure and/or increased Doppler signal within the patellar tendon27 VISA-P score < 80/100 points