Just as a note, I had the chance to watch Jeremy Wariner and his Adidas teammates warm up at a meet last spring. The Clyde Hart warmup is full of long hold stretches. It is very “old school” but it seems to work fine. Static holds before a workout appear to be fine if there is enough of a break between the stretches and the sprint activity. Wariner and friends probably sat around for a good 35 to 40 minutes pre-race.
I think the recent obsession with dynamic stretches needs to be taken with a grain of salt as it is not clearly superior to static. I’d be careful of throwing out static stretches as a potential tool. I like them early in a warmup, especially in a northern climate where it takes longer to warm up. It’s safer than swinging your joints around at high velocity before you could possibly be warm like I see tons of kids doing at meets.