The joint in your knee is a hinge joint, just like hinges on a door. It only opens so far and only in one direction.
When sitting on the saddle the leg should no be straight, the knee should have a slight bend of about 10 degrees.
When you Bend your Leg your hamstring contracts and your quadriceps relax
Yes broken kneecap and femur can still get better and can still bent again
you bend the back leg and take your skirt and hold it, and bend your legs
You haven't been to a physician? You may be in the process of causing irreparable damage. Get a move on.
they bend...
Takes practice
If you mean one leg then; Fondue. If you mean both legs then; Plie
You have either hurt your leg badly or broken it.
Mammals have a joint in the middle of the leg that is called a knee. In humans this joint allows the leg to bend backwards.
Your knee allows you to walk and bend your leg.
To bend the leg so you can walk and survive