Place the bar safely and securely on the squat rack and make sure it can't roll back or forth. Then, get under the bar and slide your whole body under while holding it in a wide grip with your palms facing away from you. Your entire body line (legs, bum, back, neck and head) should be in a straight line. Allow yourself to "hang" down. This is your starting position.
Lift yourself up to the bar all the way until the bar is just a few inches away from your upper chest line. Then, lower yourself back down in a controlled manner until you get back to the starting position. Remember not to completely extend your arms on the way back down; always maintain some tension in them.
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 do this exercise if you are an absolute beginner
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or place a weight plate on your chest.
This is a rarely used/seen exercise at the gym yet it is very effective. This is a bodyweight exercise and, as you may have heard, bodyweight exercises are super-effective for building muscle as well as toning and tightening.
This exercise looks easy, but when you do it the first time you will understand why it's such an effective exercise. On this exercise you are working against gravity and your bodyweight which makes it challenging to execute. However, if you stick with it, you will find that the exercise gets easier over time at which point you will need to think of ways to make it more difficult (such as asking a spotter to place a weight plate on your stomach or chest).