With all intermediate yoga asanas, you should listen to your body. Only go to 70% of your maximum possible movement. If you are injured or have a serious mobility problem, keep to 40% and gradually aim to work up to 70%. If the asana involves ONE leg or arm, remember to execute the asana(s) equally on both sides and in particular be aware or present In other words concentrate on what is happening within the body whilst you are doing these exercises.