

This is exacting exercise for advanced athletes.
You lock into wide cross-bar (best is with bent ends of cross-bar down to floor). With power of back muscles (not with power of arms!!!) you try to tighten to the cross-bar (you touch to the cross-bar of scruff of the neck).
Exercising is preferable with the cross-bar without middle pole you not to need tilt head in final motion (and you donīt connect also breast muscles).
You breath out with motion up and with motion down you breath in.
Primary:
m. latissimus dorsi
Secondary:
back muscles completely
m. brachii
m. biceps brachii