1- Hang your body grabbing the pull up bar with palms forward, wider than shoulder width, arms extended.
2- Bent your knees slightly and cross your feet behind, this is your starting position.
3- Pull your body up until the back of your neck reaches the bar level.
4- Lower your body slowly back to the starting position, and repeat.
Tips and Advices:
1- Concentrate on squeezing your back muscles while pulling your body up, don't let your arms do all the work.
2- Avoid cheating the exercise with body momentum while pulling your body up.
1- You can also do this exercise by keeping your back 30 degrees to the back, and your chest to reach the bar level, not the back of your neck.
2- Use machine assistance if you strength level isn't enough yet Machine Pull Ups.