In the practice of the Yang Style Taijiquan Simplified 16 Posture Form, there are certain guiding principles that every practitioner must become aware of and utilise them in their performance of the Yang Style Taijiquan Form. Especially the opening (Kai) and closing (He) actions of the elbow joints as the practitioner performs their arm movements, every joint in the body acts as a pump to mobilise the flow of the blood, lymph and Qi to circulate freely throughout the entire body to boost the immune system towards attaining good health, fitness and wellbeing from the practice of taijiquan in general.
The opening (Kai) action of the elbow joint (Zhou Jie) allows for the blood, lymph fluid and Qi to enter into the forearms, hands and fingers of the practitioner filling the arm and giving the limb a sensation of increased weight and thickness as the fluid flows through the upper extremities. This added weight in the both arms by using the opening action of the elbow joint to allow more fluid to enter the limbs, helps to maintain the bones within the arms to remain soft and pliable, as the warmth of the blood and Qi gently heats the bones penetrating deeply into the marrow (Sui) to help produce more red and white blood cells to reduce and slow the degeneration or ageing of the body and to stop the bones from becoming hard and brittle. Because of the increased fluid entering the upper extremities, an increase of weight develops in the arms as the practitioner moves their whole in the actions of their Yang Style Taijiquan Form, this added weight in the arms can actually strengthen the tendons and bones. The tendons are strengthened by being able to hold the weight of the arm in free space away from the body for some time, because the arm fills with fluid helps to give each arm a feeling of weight bearing which will strengthen the bones of the arms.
The Closing (He) action of the elbow joints allows the practitioner to control the amount of blood, lymph fluid and Qi that enters the arms. By gently bending the elbow and closing the joint slightly will slow down the circulation and allow it to gather within the elbow joints, the practitioner should gradually begin to feel and sense a slight coolness and lightness within their arms as they gently close the elbow joints in the practice of their Yang Style Taijiquan movements. When closing the elbow joint it should not fully close to the point were the forearm touches the shoulder of the same arm, there should be a slight V shape maintained between the upper arm and forearm. The practitioner should not feel any tension within the elbow joint when they begin to close it, plus the point of the elbow must point downwards towards the ground.
If the practitioner can develop the softness in their Taijiquan actions to open and close the elbow. Then the joint itself can be used to pump and control the circulation of the blood, lymph and Qi into the upper extremities. Removing any blood stasis or blockages within the energy pathways (Jingluo) that have accumulated within the arms, due to tense muscles and stiff joints.