The strengthening of the vastus medialis is of considerable importance for the patellar stabilization and the knee joint in general. As you probably know the vast medial is one is one of the four heads that form the quadriceps muscle and its main function is to extend the leg.
In the case of patellofemoral pathologies it is advisable to work by limiting the angle of flexion to the maximum, just as the orthopedist advised you (in this way you avoid the excessive compression of the patella on the femur and the possible onset of cartilaginous pathologies).
Moreover the maximum involvement of the vast media in the movement is obtained precisely in the last degrees of extension, this involvement increases further if the foot is extra-rotated (tip pointing outwards) and if a co-contraction of the adductor muscles is performed simultaneously. (for example, squeezing a ball or pillow between the thighs).
Not all leg extensions are equipped to limit the degree of flexion-extension. Technogym for example, builds adjustable leg extensions.
If your gym is not equipped with machinery of this kind, or you turn to a specialized center or you can use rubber bands or anklets and perform the exercise sitting (foot forward so that the knee is semi-flexed (45 °), toe to the outside, extend the leg just like you do in the leg extension, repeat 20-30 times and change limb).
Regarding the stretching of the ischiocrural muscles you can perform the following exercises in a slow and controlled way.
Sincerely.
