Wisdom of Our Forefathers

My teacher was talking about relaxing our kua today, and it struck me how much study our forefathers put into developing taijiquan. They must have studied human anatomy very closely and realised that usually, when we move, the hip swings together with the legs (the femur and pelvis move together, just watch any pretty lady walking down the street :) And they developed taijiquan to exploit this. When leg and hip move as one, a person's centre of gravity can easily be moved. By practising and learning to relax the kua, so that hip and leg do not move as one, a taijiquan practitioner is able to move his upper body freely and yet maintain his centre of gravity. So he is able to move his opponent while holding his ground.