Well, i'm 14 and play in high school. I am 5' 10 and 180 pounds. I had a good season, however as a fullback and a middle linebacker I was a little bit slow. I also have relatively small thighs, for next season I would like to get stronger, faster legs. I've been squatting a little bit but the bar on my back hurts so badly I can only do the exercise for so long. Any ideas for a good leg workout?