A lat pull down will move the shoulder and elbow the most, primary is probably shoulder.
During a shoulder press, the primary joint actions are shoulder flexion and elbow extension. The shoulder joint allows for the movement of raising your arm overhead, while the elbow joint extends to push the weight up. Additionally, there is some scapular movement involved to stabilize the shoulder blades during the press.
The primary flexors of the shoulder joint include the anterior deltoid and the pectoralis major muscles. These muscles work together to bring the arm forward and across the body.
Elevation of the humerus and slight medial roataion of the shoulder. The anterior deltiod is a semi-weak muscle.
Because shoulder horizontal adduction is performed when the arm is horizontal position (i.e., the elbow is level with shoulder) and adduction is movement toward the center of the body, shoulder horizontal adduction is performed primarily by pectoralis major and anterior deltoid, with an assist by latissimus dorsi.
shoulder flexion shoulder adduction shoulder horizontal extension
During a sit-up, the primary joint movements that occur are hip flexion as the hips bend, lumbar spine flexion as the back rounds forward, and thoracic spine flexion as the upper body moves towards the knees. The shoulder movement might also involve slight flexion as the arms reach forward towards the knees.
Defeat Armored Targets
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Infraspinatus.
the forward, or striker.
The synergist muscle performs the same movement as the primary mover. This often depends of the position of the joint.