Patellar tendinopathy, or Jumper's knee, is a painful knee condition caused by inflammation of the patella tendon. This condition is most frequently observed in subjects who play sports that require repetitive regular jumping. Jumper's knee is frequently misdiagnosed as a minor injury and many athletes, like our patient, keep on training and competing and either tend to ignore the injury or attempt to treat it themselves. However, jumper's knee is a serious condition that requires a correct and timely diagnosis, which often necessitates ultrasound investigation in order to start the most appropriate treatment.