I've always been thinking about hyper-extension but never got round to researching on it.
My teacher always encouraged keeping heels together in first position..and I thought she was being fussy in the past until I became a teacher...and it all makes sense now! I've been controlling my own minimal hyper-extension quite successfully, and corrected students with more pronounced hyper-extensions. I read an article by Lisa Howell recently and that was only when I got more concerned about my student's hyper-extensions. Since there are so many articles online already.. I think I can sit back and let you guys do the clicking =P
Dance.net -- Little Moomoo's post (has useful tips on feet exercises as well)
This blog article was first published in February 2009.