Injury rates. Statistically, stretching increases injury rates for some sports as well as causing injuries. I tore a hamstring with static stretching. It'll probably bother me the rest of my life. I still stretch just because it makes me more comfortable in my daily life. However I don't stretch to the extent that I used to. The reason for some increased sport injuries is because it allows joint movements which are contraindicated in some sports. Things can get out of alignment and then bloooey.