What is the shoulder joint action during the down phase of a push-up?

During the down phase of a push-up, the shoulder joint experiences horizontal extension. This occurs as the arms are lowered towards the floor, moving the upper arms away from the midline of the body.

In more detail, horizontal extension at the shoulder involves the movement of the arm backward in relation to the torso when the person is in a prone position and lowering themselves. This action primarily engages the posterior deltoid, the teres major, and the infraspinatus muscles, among others, to control the descent and stabilize the shoulder joint.

Understanding this motion is essential for assessing upper body strength and performance in exercises involving pushing movements. It is also key for developing effective training programs that target the appropriate muscle groups involved in shoulder stability and strength during functional movements.