Hi everybody, i am 17 years old, 180,5 cm and 78 kg. I have started Taekwondo for 3 months, my problem is is i can't do the roundhouse kick, after i can do the front kick well, i learned the roundhouse kick, but when i turn my waist to do the kick, my hip is really low, after turning my waist, my thigh only make a 50 degree with the floor (step 4 http://taekwonwoo.net/images/kick/round house kick.jpg). i think one factor that make me hard to do the round kick is that my thigh is really weak. Is their any exercise to make my hip become more flexible and become higher when i do the roundhouse kick? And can i become flexible enough to train taekwondo and kick to the head if i am 17 and really not flexible? Hoping for some advices, thanks a lot.