The second method is Bone: gu骨.  Its states Bone power collects internally– gu jing nei lian (骨劲内敛).   On the basic level this method is associated with proper movement and alignment of structure.  Head up, chin in, back straight, your joints aligned and working in harmony.  If one part moves everything moves; if one part is still it is all still.  Many internal martial arts talk about 3 tips, 3 external harmonies, 9 joints, 3 hearts and within some Liu He Ba Fa lineages masters talk of the 9 joints and 5 hearts.  The intent of all these ideas are the same.  To move in a coordinated manner to create maximum force in the most effective manner.  Whether moving fast, slow, soft, or hard all effort must be made with all parts of the body in the correction direction.  If you hand falls but your  foot does not its incomplete.  If your foot falls but your hand does not the same inefficiency happens.  Everything must be coordinated.  Some internal arts fall with a flat foot during certain movements and others use a heel to toe effect.  In the end if your dan tians (upper, middle, lower) are in line and your hands and feet, knees and elbows, shoulders and kua move in unison you will find the harmony in your body. These harmonies can also be broken down farther into sections like shoulder, elbow, wrist and farther still into wrist, palm, and finger.  The more micro you can make it and feel it connected the more connection you will potentially make.  Some Liu He Ba Fa move their body in total unison while others follow more of a water principle and have a wave like effect among their joints.  I will not say one way is more correct than the other as long as in the end they work towards such jins as Hua Jin, Lou Shan Jin, and other energy expressions.

Yet there are deeper levels as well. Some sources talk of bone marrow as a source of Qi production due to the fact your first treasure (Jing) is used in TCM to make bone marrow. It is said when you are born your marrow is full, as one ages Yuan (pre-natal) Qi and Yuan Jing are gradually consumed and depleted.  So one must return to their origin and nourish the marrow.   Even Qigong sets are conducted with this process of renewing and rejuvenating bone marrow — i.e.  Marrow washing (usually associated with muscle/tendon changing qigong).  If your Qi is abundant it will naturally fill your bones and will be identified with a person having strong teeth.  Back in the turn of the century, masters with their Si Shou filled could tear metal with their teeth; something not readily seen now-a-days.  It helps to conduct Qi Gong or Liu He Ba Fa  with an inward intent at some point in your training, towards your bones and dan tian.  Working on condensing and expanding your qi with your breath.  The movement of Qi into the bones will strengthen them, rejuvenate them, and help rid your body of potential disease and illness.