Sit down on a flat bench and place the barbell behind your head resting on your traps and shoulders. Keep your back straight. This is your starting position.
Lower your upper body down all the way until your chest touches your legs. Keep your back straight and head straight in the same line (no need to raise your head and try to look up into the horizon). Then, go back up to the starting position and repeat entire movement for the desired or prescribed number of repetitions.
Perform this exercise in a smooth and fluid motion
Keep your back straight at all times
Don't do this exercise too fast; no jerking motions up or down as 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 with very light weightplates.
This is a great exercise for everyone - beginners and advanced lifters alike. For beginners, the seated position is a great start and the unloaded bar is the best way to go until your back gets stronger.
This exercise will get your lower back tight, strong and in shape fairly quick. The key is not to rush it and make sure you stretch before and after. Stretching out your back after you do this exercise is very important as you will find your lower back muscles getting really tight from performing this exercise. Nothing to worry about as that is normal and expected - that just shows that you are "hitting the spot" and the exercise is very effective in working the intended muscle group - the lower back.