From your starting stance, begins when you step back with the front foot, and bring your hands together over your head 180˚
Upward rotation of both scapulas with middle/lower fibers of the trapezius muscle and serratus anterior muscle.
Flex shoulder joint 180˚ by concentrically contracting your anterior deltoid and upper pectoralis major muscles.
Elbow flexes about 45˚ by concentrically contracting both heads of the biceps brachii, brachialis, and brachioradialis muscles.
With the leg you take your back step with, your hip extends concentrically by using your semitendinosus, semimembranosus, biceps femoris, and gluteus maximus muscles. This causes a posterior pelvic tilt.
Remain extended 180˚ by concentrically contracting your rectus femoris, vastus intermedius, vastus lateralis, and vastus medalis.