Stretch? How Long?

In my last posting, I alluded to the fact that I would explore the research on prolonged stretches and how long. I have always heard anywhere from 10-60 secs holds to increase flexibility.  The following study identifies that the 30 secs holds is the so called "sweet spot".  It did however find that 15 secs holds had no significant changes in flexibility and 60 secs was slightly less effective than 30 secs.  So if you aren't holding your stretches for more than 15 seconds the likelihood is that you are wasting your time.  Although this helps solidify the 30 second rule, this study did not specifically mention how many times the participants were performing per session.

http://physther.net/content/74/9/845.full.pdf