At my middle school, we have the best gym in Northern California. State of the Art equipment, better than most high schools in America even. I signed up for it in the beginning of 7th grade as a 5'4" ,approx 115 lbs with 20-25% bodyfat. I finished with 5'7", 128 lbs with 10-15% bodyfat.

Probably because of knowing I could become successful and be able to beat others if they got in a fight with me. It also built my confidence and my determination. Better chance of getting to play football in high school, too. It's not for the weak and delicate.