Grab the barbell at shoulder-width apart (or even a bit wider). The palms of your hands should be facing towards you and your upper body needs to be bent to 45% degrees approximately. This is your starting position.
Raise the barbell up as if you are trying to pull it into your lower-to-mid stomach area. Then, slowly lower it back down again to the starting position.
Repeat entire movement for the desired or prescribed number of repetitions.
Perform this exercise in a smooth and fluid motion
Don't extended your arms completely on the downward portion of the movement
Don't arch your back; keep it straight at all times
Don't jerk the weight up; this may result in lower back injury
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or load the barbell more.
This is a great exercise for building back muscles. As with most free weight barbell exercises, this exercise is very efficient in growing your lats and taking them to the next level of muscular development.
The important thing to point out here is that your posture needs to be perfect when performing this exercise. If you hunch your back (also termed "rounding" of the back) you will achieve nothing other than put unwanted pressure on your lower back muscles. Thus, take a few moments and get into the right position before you start doing repetitions.