They simultaneously work opposing muscle groups, don't necessarily require the use of specialized equipment and are simply one of the most effective exercises for building upper body mass and strength. (fitnessandpower.com)
At its base there is a great working principle that can be beneficial even to natural bodybuilders, namely — training of opposing muscle groups. (fitnessandpower.com)
The last two moves for opposing muscle groups are here because they often fail to deliver what the user really wants. (flippingfifty.com)