Hi. I had TPF injury while running as well at 36 yo. You really have to keep pushing your flexing. I sometimes took painkillers before pt so I could push harder. I probably worked on it for an hour, if not more, each day. I do have my range of motion back but I still have to keep flexing it or I lose it again. I am 8 months post op. I think there is a procedure that they put you under and then force the flex in your knee. I really didn’t want to go that route so I don’t know much about it. I do think that can help though if you aren’t successful in pt.