Ok.. I'm 15 years old.. 133 lbs and im about 5' 7 1/2.. track practice just started for this year. But I'm not going to do it this year due to an injury i had about 3 monthes ago.. I tore a ligiment in my left ankle, and the doctor says it's still healing a little bit. But I do want to do track next year, and I want to know what I need to do if I'm going to be a sprinter. I do work out about every other day lifting weights and I go a mile on a resistance bike. I'm wondering what I need to do in order to get faster in a year, and what I need to do for better endurance..