Nice writeup and research. Personally iv been stretching post workout, and it has helped me alot. iv been into bodybuilding on and off, since past 15 years. I use to start my workout with a bit of stretching, but it use to cause more muscle pulls. After reading alot of articles of pro old school bodybuilders like arnold and bill pearl, i started stretching post workout. I guess for runners, a bit of warmup with stretching might be good. so i guess it completely depends on exercises.