Your deltoid is a large, triangle-shaped muscle that supports the movement and stability of the shoulder joint. This muscle covers the upper arm and forms the rounded contour of the shoulder.
Functionally, the biceps are key players in elbow flexion (bending the arm), forearm supination (rotating the forearm so the palm faces upward, like turning a doorknob or opening a jar), and shoulder ...
Muscle testing is also known as applied kinesiology ... which states, “for every action in nature, there is an equal and opposite reaction.” AK applies this concept to the human body.