In common usage, the human leg is the lower limb of the body, extending from the hip to the ankle, and including the thigh, the knee, and the cnemis. The largest bone in the human body, the femur, is in the leg. In human anatomical terms, the leg is the part of the lower limb that lies between the knee and the ankle, and the term "lower limb" is used...
make sure to sink your heels down, and keep your weight centered. Also work on leg strenghth, try standing on the edge of a step with your heels hanging off...