Phys Ed - Stretching - The Truth - NYTimes.com
http://www.nytimes.com/2008/11/02/sports/playmagazine/112pewarm.html?_r=2&oref=slogin&oref=slogin
180度開脚する方法 体が硬い人のためのストレッチ体操
http://diet.netabon.com/exercise/stretch/180stretch.html