After the students training in stance, movement, and footwork, the next area of importance is joint rotations. Rotations are vital for all levels of health, age, and body type.
Most major joints of the body contain a capsule and within that capsule is synovial fluid, used for the lubrication of the joint. The only thing that circulates the synovial fluid is when the joint is operated to the full extent that it can move. If a joint is not rotated correctly, through its range of motion, there will be a lack of circulation of this lubricant and eventually the joint will be compromised. In addition, the joint itself is surrounded by connective tissue, ligaments, the integumentary system, and muscles. Also, by moving the joint through its full range of motion, it keeps these structures balanced. This is where the idea of exercise injury comes from. Repetitive Strain Injury (RSI) is not really the correct verbiage, it comes from not fully exercising all the muscles in a way that is not harmonious to the joint. If you can repeat a healthy way of moving, over and over, it is beneficial not detrimental.
Way too many people do one type of exercise that begins to strengthen only one or two of the muscles surrounding the joint. This begins unbalancing the joint, and the muscles will pull the bones out of alignment. When the muscles are out of alignment the joint cannot operate to its fullest extent and starts to become compromised.
It is through exercising the full range of motion with a joint rotation, as well as your regular exercises, that keeps the joint healthy, properly lubricated and in alignment. For those of you with the understanding of the internal arts, chi is primarily blocked at the joints. So the first place chi gets jammed up is at the joints. You cannot run water through a hose if the connectors and couplings are corroded.
Another benefit of joint movement is that these are your levers and fulcrums of the body. The deeper the knowledge of levers and fulcrums, the better the balance, the better the structure, and therefore the better quality strength, variations and subtleties of movements are possible.