Unfortunately I was not blessed with the best knees. I am only 24 years old, 6ft, and 200 lbs. I have a long term goal of competing in the 24 hour sniper challenge next year, and have started training early. However I am a week into it and I can barely walk due to the pain in my knees. I have brought it up to my doctor and he doesn't think I need to do anything and the pain will go away. I ice them every night, but that only brings relief for a few hours. Does anyone have any suggestions for some physical training exercises for my knees?