Classical Tai Chi individual moves footwork

Video of how to do footwork

I never hear feedback from my Classical Tai Chi students regarding difficulty in doing this, this is reasonable to understand...they do not yet know what it feels like. So, the teacher, a mirror or one's own personal video to monitor the moves and one sees they are pushing with either front or back foot. Also, important to check stance, structure, distance between feet, etc. To the nitty gritty of this they are really in the beginning and most difficult stage where they are learning to gain and keep attention in the core region. Any attention on the leg as evidenced when one pushes then the move will be partially initiated by the leg and as you say "external" movement. I like the expression "...it feels like a suction force pulling the body..." when pulling. If done correctly there will be no feedback of sensation from the leg. If pushing one first feels sensation in the calf, if pulling one feels just the sole of the foot as it seemingly "grips" the floor...no feedback of the leg, calf, thigh, etc.