I did have problem about my knee for other reason, 2 exercices good I remain from my doctor was :
+ Cycle on an "appartment bike" : 1 min normal, 1 min with open feets like "duck"
+ Push at the press bodybuilding machine (low weight), 5 normal, 5 open feets
PS : feets are to be opened a bit (not 180°

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Cycling actually started this injury back in the day (cycling through a huge storm in open fields from one city to another)... I still don't like cycling anymore. But I do cycle in the gym sometimes and it doesn't seem to add to my problem anymore. Next time I'll give this excersice a try, anything I can do to improve faster I'll try

The excersice I got is one for my upperleg, low weight, slowly up and even slower bringing it down again. It's burning like hell after a few times, but I do feel it working on the excact spot where I have a problem, so I will continue this excersice and see what happens. I hate the leggpress, but I could give that one a try aswell.