Because I'm convinced that not stretching before runs has contributed to my injuries. And cold stretching in between run days has helped noticeably. When I had ITB flare ups, I noticed that cold stretching the ITB (advice from a phys therapist) and stretching the hammy made this problem go away quickly. I realize that cold stretching is a dirty phrase these days but my running injuries started to mount after following the "no stretching until warmed up" school of thought. I still stretch after runs which doesn't seem to matter at all in the way my body feels right after but I do it because I know it'll help keep things from getting too tight later that day. I seem to know my limits as to how far and how much I can push a cold stretch. What can I say, a routine of cold stretching seems to be working well for me and has made a positive difference.