static stretching does lead to a loss on strength with the workout following, I've found from my personal experience. although stretching is still good if it is done for shorter amounts of time since it helps maintain and increase flexibility. and also, the only stretching i ever do is based around my shoulder joints since i've busted them up so many times from not doing so. with legs,chest, biceps, lower back and tri's i've found that two warmup sets of high reps ( 15-20) with relatively light weights is way better than any stretching.