Not to confuse back exercises with Lower Back Exercises, trapezius, or rhomboids, these are a completely different set of muscles. The Latissimus Dorsi muscle group are the largest muscles of the upper body, they originate from the spine and spread fan-like along the back and collects into a rope, and insert into the humerus, the bone on the upper arm under the triceps. The Latissimus Dorsi is a powerful muscle responsible for extension, adduction, transverse extension also known as horizontal abduction. When looking at the muscle it resembles wings, causing a downward rotation of the scapula during a pull-up.
Agonist – Posterior Deltoid,
Antagonist – Anterior Deltoid,