This confusion comes because non-dancers usually call all these movements 'kick' while for a correct dance technique we distinguish between flicks and kicks.
Most figures use a flick and that has three phases:
- an initial raise of the knee
- straightening of the leg with toe pointing to the floor or at max. horizontally
- raise of the knee again.
So at a flick the knee is bent before and after the main action.
For a kick the leg is raised without that knee action.
We can say: at a flick the main action is made from the knee while at a kick (seldom used) the main action is in the whole leg, swung from the hip.