This exercise works the lats, spinal erectors, traps, rear deltoids, biceps, and forearms.
Stand with your legs on each side of the T-bar. Grab the handle with both hands. Slightly bend your knees to take the stress off the lower back. Keep your upper body at a 45-degree angle with the floor. Let your arms hang down in front.
Use your lats and arm strength to pull the T-bar up and row it into your abdomen. Arch your back and squeeze your lats together to maximize the peak contraction in the back muscles. Slowly lower the T-bar back to the starting position. Repeat.
Tip - for variety you can do this exercise with a reverse grip to hit the back muscles from a different angle.
source: www.leehayward.com