When I do leg extensions I only feel it right below my knee...I have it at a low weight setting. I used to run cross country, like 5 years ago, and when I did leg extensions then it was the same thing. Is this a sign of knee problems or just really weak muscles?
You should feel it just above the knee, and up into the quads. Make sure you have the machine properly adjusted, and give a pause at the top of the movement.