Internal Discipline and good structure
Sifu Jason Bulger is demonstrating a practice I devised for the internal movement in the core that takes place right before you take any step in Classical Tai Chi whether "walking", "Form", etc. Note he turns the foot to several angles, has toe down when lifting, toes up when "stepping". But actually, he could be kicking at any angle. Also, a signature sign that internal movement is taking place in any movement is the "crimping" movement that one's clothing in the torso makes before a limb moves and that can be seen by even the uninitiated. There is a definite "crimp" and not just slight movement. This is why Master Hwa has on repeated occasion, urged me to wear close-fitting shirts in order for students to not only see the movement but to see that internal precedes external. In other words, in the case of Classical Tai Chi walking the core movement precedes/leads the lift and lower of the leg, arm, etc.
In Uncovering the Treasure p. 16 by Stephen Hwa Ph.D., re. health benefits of Classical Tai Chi: "We often see the elderly walking with a shuffle -- the walking movement no longer extends into the torso...one may assert that the onset of internal rigor mortis actually precedes death!"
Additionally, not only is the "internal rigor mortis" he speaks of an issue, but being challenged by balance problems with everyday walking is an issue as well. When we consider that putting one foot in front of the other requires balance, when we consider that day to day walking requires us to balance on first one foot then the other...aren't we always doing this with the risk of losing our balance?