One of the back's main functions is the movement of the shoulders back and forth and it is this that is often neglected during back exercises. To get the most out of a rowing exercise you must pull the shoulders and shoulder blades back fully - technically called 'scapular retraction'. By doing so, you ensure maximum recruitment and contraction of the lats and mid-back muscles.

Unfortunately, most people simply move their arms on heavy rows, bending at the elbow to complete each rep. The scapula never rotates backwards and the shoulder stays rounded forwards, meaning that the back muscles haven't fully contracted during the rep - which translates to wasted effort and very little muscle development.