Here recently, I've been reading a lot on opinions concerning what type of training methods are categorized as 'the best'. Undoubtedly, if this method had been found and proven there would be no reason at all for trial and error and everyone with a well-balanced, strength and hypertrophy program would have identical routines and diets; in a perfect world this would be true, but unfortunately, it isn't.
The fact is, balancing out the stimulation that antagonists and agonists receive in a single mesocycle is the absolute best approach for balancing out exercises. This type of training is called antagonistic training and revolves training the antagonists of each muscle evenly by stimulating the reverse force in the same plane with the same volume, intensity, frequency and sometimes even time under tension.
Your body works in three planes: transverse, sagittal, and coronal. The movement that your joint makes determines which of these planes are going to be utilized during this specific exercise. For example, any exercise involving abduction, adduction, inversion, eversion, depression or elevation would be categorized in the 'coronal plane'. The coronal plane also is defined as the plane that separates the body into ventral and dorsal (front or back). Any exercise involving flexion, extension, dorsiflexion, or plantarflexion is categorized as in the sagittal plane. And any exercise involving anything horizontally is in the transverse plane.
If you would take this bit of information and make it simple, each and every action opposes one another in a sense. For example, abduction focused exercises may focus on a particular set of muscles while adduction focus on the antagonists (muscles that oppose the agonist) of that particular range of motion. Just like plantarflexion of the ankle opposes dorsiflexion of the ankle. This allows you to take two movements from each plane and have them balance out one another. In this sense, you could come up with this being properly balanced.
Each routine acquiring a horizontal push/pull, vertical push/pull, squat, and deadlift would acquire two exercises from the coronal plane (overhead press; pullup); two exercises, from the transverse plane (bench press/barbell row); and finally two exercises from the saggital plane (squat and deadlift). These movements all tend to balance each other out well. Just like the barbell row will focus on the humerus' external rotators and scapulae retractors in the same stimulation and stress that the bench press will put on the humerus' internal rotators and the scapulae' protractors; they just tend to balance each other out.
Every movement of the human body will involve working around a single joint whether that joint be a hinge joint that only allows flexion or extension or a ball in socket joint that will abduct, adduct, flex, extend, and internally and externally rotate. Both the elbow (a hinge joint) and the hip (a ball in socket joint) are classified as synovial joints, but they acquire different ranges of motion. This shows that regardless of the joint type, it will be based in either the transverse, sagittal or coronal plane. And, by all means, will have an opposing action to balance the other out in the same plane.
For every push, there should be an opposing pull to balance it!