If you are on your back with your hips and knees in flexion, your legs make a triangle with your knees at the peak.
It is Flexion and Extension
list movements for trunk flexion
plantar flexion and knee flexion
Plantar flexion occurs in your feet.
balance
balance
Flexion (noun) = the action of bending or the condition of being bent, especially the bending of a limb or joint. "flexion of the fingers"
Elbow flexion, shoulder flexion and supination of the forearm.
This movement is called flexion. It reduces the angle between the bones at a joint, typically involving the bending of the knee or elbow.
Extension is the opposite of flexion.
contract shorten shrink sever