Dr, Lieberman's theoretical basis, at:
http://www.parkinsonresearchfoundati...349&Itemid=104
http://www.parkinsonresearchfoundati...d=79&Itemid=95
http://www.parkinsonresearchfoundati...=219&Itemid=83
examples of active exercise:
Cycling: Inevergiveup.org, tandem bycicling, static byke.
Examples of passive exercise:
As mentioned by Dr. Lieberman: acceleration therapeutics, EECP,and found elsewhere, blood modulation therapy.