Suggestions for a Sprinter

I'm 15 and just had my first year of high school track and decided I'm gona try and really up my speed from last year, I was running in the 11.8 - 11.9 range and so far this summer I've been running on one of those crosstrainers for about 15 minutes maybe 5 or 6 days a week on near max resistance doing those excercises on it where you start slowly and then build yourself up to a sprinting speed and then start back slowly again and so on, I've also started with weight training and have been doing some ab work since I heard that can help too but the thing is I'm not very flexible, I'm pretty strong and I'm about 5'10" and 160 pounds but I don't have the flexibility, if anyone can help me with any stretches that could help it would really be appreciated since I'm thinking that improving my flexibility will go a long way to improving my speed

you are speedtd arent you?

11s as a freshmen is moving bro. Let me put in my two cents, yes flexibility is a big thing but you have to think about why. if your legs can stretch forward and backward while running with less resistance it takes less work to deliver longer and faster steps. being unflexible your legs will naturally not want to extend to where they should and will try to pull themselves down where they are comfortable and it takes more power for you to push your legs out to do a maximum stride.

the areas that need to be stretched are of course the back of the thighs, calves, even and lower back dont forget that one. but just as important is the front including your hamstrings, shins, and the one people never do is their abs. Dont waste your time trying to do the splitz use common sense and think about where you need to lose resistence to sprint.