This athlete may have amazing concentric and eccentric strength in the barbell bench press but might be weak and unstable when
they horizontally adduct and internally rotate the arm to fully contract their pec.
For example, with the pectorals you would have to know that to fully contract your chest you would have to
horizontally adduct the arm and internally rotate the shoulder.
I would have this individual stand up, straighten out their arm, internally rotate their shoulder and bring it across the body (
horizontally adduct with internal rotation) and press it against an immovable object for about 5 to 10 seconds at about 50 % effort.
The pectoralis major
horizontally adducts the shoulder.