Hi, my horse is really heavy in the forehand, making it difficult for him to lope. He CAN lope but it's like he is dragging himself along with his forehand. I hear hill work I good but I don't have acess to any hills, only an indoor arena and outdoor arena. What are some exercises to build muscle in his hind end? Also how do you get a horse on the bit? And how do you know if they are on the bit? Thank you