Is every Classical Tai Chi movement internal?

Internal Discipline in Tai Chi walk (see the link) "Very good discussion here and even bobbing the knee up and down while "walking" is a clear case of what is called localized nerve activity that one needs to minimize and eventually stop. Other foot movements really involve the power from the torso which moves the entire leg. Even the lift of the toe when sitting back should be an integral part of the sitting back and engaging the torso, not an isolated move of lifting the toe. The Tai Chi Form is developed such that every arm movement, every leg movement is initiated from internal movement so that the circulation of internal energy and qi will maintain continuity during Form playing. My students in the class often mention that they thought I just externally moved the arm or the foot in certain Form movements, but later realize that it is actually internally driven. They would ask, "Is that internal, is this internal?" My answer is always yes. "  Stephen Hwa, Ph.D.