When you straighten your leg, the quadricep muscles pull on the quadricep tendon, this pulls the kneecap to make the knee extend.
How do you contract your quads?
Here is how you do it:
- Lie on your back and use a yoga block or basketball to prop your knee up.
- Slowly straighten your bent knee until it is all the way straight.
- Tighten your quad muscle with your toes pointed toward the ceiling and hold it tight for five seconds.
- Slowly lower your leg down.
- Repeat for 15 repetitions.
What happens to quadriceps when sitting?
Sitting puts you in a position with the rectus femoris in a shortened position. The more the quadriceps shorten and tighten, the greater the chance of chronic muscle tension in your lower back muscles.