although there are many variations of the basic body position it essentially involves the skydiver moving out of the traditional face-to-earth & arched position, and straightening the legs, bringing the arms to the sides and de-arching, using the body to cup the air as a means of providing greater lift. there is debate over what exactly constitutes the most efficient tracking position (providing the best glide ratio) especially concerning how far (if at all) the skydiver's legs should be spread. some variations of the tracking position work well for some individuals and not so well for others. also, when a skydiver gains experience, his or her preferred body position often changes.