I was a short, white, halfback in high school. My 40 time went from a 5 flat as a freshman to a 4.5 by my junior year.I agree with some of the posts above, squat and power clean are great exercises to increase speed. Creatine is a good supplement. Take it with grape juice so it will load into your muscles better. Drink plenty of water while on it. Cycle it, take it six weeks on six weeks off. Also, I found that for increasing strength the Buckeye Power Workout works well. Find out your max for power clean, squat, bench, and incline ,then use the buckeye to increase your strength in these core lifts. Hammer curls are good for helping you hold onto the ball. Working calves is good for everything. Stay away from alcohol it eats muscle and avoid it especially while taking creatine, its worse then for some reason. Stay away from the roids especially while you're in high school. They may stunt growth. Also, stanozolol or winstrol , probably the most popular, can make you tear hamstrings ,ligaments etc. That's enough for now. Good luck and keep plugging. If you keep working someone will get hurt, fail, whatever and you'll get your shot.