jarmo
The hole in your tendon is most likely mucoid degeneration within the tendon, but probably doesnt cause your pain. You wont get rid of it either, so don't bother getting another ultrasound to check. The other replies are on track regards to biomechanics, technique etc. Other areas to work on may include pelvic/ core stability, calf muscle endurance and ankle dorsiflexion ROM. It is probably best to stick with the term jumper's knee or tendonopathy as the pathology of the condition typically shows an absence of inflammatory cells at the lesion. Hope this is useful for you.
Crackers