My wife learned about the book Natural Flexibility http://www.amazon.com/Natural-Flexibility-Risk-Free-Alternative-Stretching/dp/1578262844 http://www.amazon.c

My wife learned about the book Natural Flexibility http://www.amazon.com/Natural-Flexibility-Risk-Free-Alternative-Stretching/dp/1578262844 http://www.amazon.com/Natural-Flexibility-Risk-Free-Alternat... by Charles Kenny, M.D., and has found it helpful for maintaining injury-free flexibility for a variety of exercises.