A program for stronger quadreceps for STACK magazine, with links to videos of a variety of exercises
http://www.stack.com/2012/11/20/quad-exercises/
Some of my own notes :
The Bulgarian Split Squat - hits muscles in a different way than regular squats, I notice more post exercise stiffness using this than almost all other squats
The Glute-Ham Raise video - this is not an exercise where the back bends/extends. Note the form used in the video.