The cable T-bar row is a way to simulate rows on a T-bar bench. This keeps the trunk supported on a bench, which means the motion is a strict row, and there is no stress on the lower back.
 
Set an incline bench in front of a cable stack at an angle that creates as close to perpendicular line of pull to the trunk as possible. You may need to prevent the bench from sliding forward by wedging something between it and the stack machine.
 
Hold the handle with your chosen grip—generally about shoulder-width—and pull the bar toward the abdomen, squeezing your shoulder blades back together and down. Ideally use a bar with a curve that allows you to pull to end range without being stopped by the bench.
 
Lower under control into a full reach.
 
Purpose
The cable T-bar row is a basic back strength exercise that helps develop the upper and middle back, the rear delts, biceps and forearms. It’s a good choice to eliminate the stress on the lower back or potential strain of the bent row, or to force strict execution by eliminating any trunk motion. It serves a basic protective function for the shoulders and elbows by helping to balance strength development around the joints.
 
Programming
Sets of 5-15 reps are usually appropriate to suit the desired loading in a given session.  
 
Variations
The cable T-bar row can be done with any handle and grip width or position to change the emphasis, and the tempo can be changed, including using pauses at the end of the pull.