My student is entering his 2nd year in a Master's Degree Occupational Therapy program. He is also very good with anatomy because he is a teaching assistant in the dissection lab. He tells me these "pnf" PNF stretching, or proprioceptive neuromuscular facilitation stretching techniques look very similar to movements in Master Hwa's "10 exercises"...and I think they do as well, for instance "d1" flexion (click lower left picture) looks like exercise e8. In discussing this with him he made the point that OT in general works upper body while PT works lower...yet Tai Chi works both ends of the spectrum in a holistic manner.