So...I'm very interested in the Daobum take on this. As there are a lot of traditional martial arts practitioners here -- as well as the qigong / internal stuff and a few who lift weights, run, etc -- I'm curious to know how flexible we are and what our current preferred methods of increasing flexibility and mobility are. I know of various methods, and have tried all I've learnt of, but I'd be interested to know if there are others, or better ways of performing them, and what has worked for you.
As for me:
I've been working on my flexibility for a while now. I was incredibly inflexible to begin with, unable to touch my toes with straight legs by about 30cm; unable to think about getting into the splits; unable to do a back bridge; terrible scapular mobility, etc. Now, I can not only touch my toes but grab my foot; getting closer to the splits; decent back bridge (spinal mobility needs a lot of work); vastly improved scapular mobility; etc.
In the last 12-18 months I've tried various stretching methods -- static, dynamic, ballistic, loaded, sinew -- and have decided that, though different people and different muscles require different approaches, ballistic stretching has an undeservedly bad reputation. It has gotten me as far in the last 2-3 months as all the other methods did in almost a year. One has to be careful, to be sure, and I'm sure it's not for everyone, nor for every muscle, but for my hamstring and hip adductor muscles it has helped enormously.
I'll share more if anyone's interested but really I'd like to hear your experience, so... please...