Your lats do activate when your shoulder shifts into extension (moves your arms closer into your torso) as you work to keep the bar close into the body, but it's not a great builder of the muscle.

Deltoid Abduction of the shoulder (moving the arm outwards and away from the body) Outward arm action in a jumping jack Rotator cuffs A group of stabilising muscles of the shoulder which helps to ...

The shoulder and hip joints are both ball and ... Allows bending (flexion) and straightening (extension). Muscles which move the knee are quadriceps and hamstrings. Ball and socket joint.