This is an excerpt from Weight Training-4th Edition by Thomas R. Baechle & Roger W. Earle.
Begin with your feet shoulder-width apart and your shoulders slightly higher—10 to 30 degrees—than your hips (figure 5.1a). Your back should be flat, abdominal muscles contracted, elbows straight, knees slightly flexed, and eyes looking at the floor about 2 feet (61 cm) ahead of the bar. Grasp the bar in a palms-down overhand grip with thumbs around the bar. Your hands should be evenly spaced 4 to 6 inches (10-15 cm) wider than shoulder width.
Pull the bar upward in a straight line (figure 5.1b). Exhale as the bar nears your chest during the upward movement. Pull in a slow, controlled manner until the bar touches your chest near the nipples (or, for women, just below your breasts). Your torso should remain rigid throughout the exercise, with no bouncing or jerking.
The bar does not touch your chest.
Reduce the weight on the bar and concentrate on touching your chest with the bar.
When the bar touches your chest, pause momentarily before beginning the downward movement (figure 5.1a ). Inhale during the downward movement. Slowly lower the bar in a straight line to the starting position without letting the weight touch or bounce off the floor.
Be sure to keep your knees slightly flexed during the upward and downward movements to avoid placing excessive stress on your low back.
Your upper back is rounded.
Lift your head, slightly arch your back, and focus on a spot on the floor about 2 feet (61 cm) ahead of the bar.
Your knees are locked.
Flex your knees slightly to reduce stress on your low back.
Your upper torso is not stable and moves up and down.
Have someone place a hand on your upper back to help remind you of the proper position.
Although the bent-over row is considered to be one of the best exercises for the upper back, it is also frequently performed with bad technique or modified more than usual. Do not be tempted to use a heavier weight, thinking that it will increase your strength faster. Attempting to lift too much weight leads to bad technique and possible injury. Another mistake is to pull upward, simultaneously lifting with your legs and low back, and then quickly leaning forward to make contact with the bar. Too much forward lean combined with nearly or fully extended knees results in a significant amount of stress on the low back and increases your risk of injury.