What do you call this leg movement in English?

I'd call that bouncing your leg. Restless leg to me is a terrible condition when you try to sleep at night and it feels like your leg muscles itch and burn and have to be flexed, or else it hurts. (Someone else in this thread said this is restless leg syndrome so I figured I'd explain).

Bouncing or jiggling.

Leg bouncing, or stimming, if associated with autism.

I'd call it bouncing a knee. Maybe jiggling, or fidgeting.

Shaking. She/he shakes her/his leg when restless.

Bouncing or shaking. Usually bouncing.

shaking kitty syndrome. Just joking It’s typically referred to as “bouncing your leg”

restless leg syndrome

Probably just "bouncing". More specifically you might say "Bouncing on the ball of their foot".

I call it "bouncing" my leg 

I would not call that “bouncing”. I would use bouncing only for more distinct, purposeful, slow bounces. For that behaviour I would say jittering of the leg. I could also see jiggling or shaking as words that I’d find appropriate.

Rock climbers call it the sewing machine. 

Ahahha im doing it right now, yea I agree its bouncing

For me that would be "jiggling".

Jiggling.