A pull-up performed without any swinging is called a dead-hang pull-up. Proponents of dead-hang pull-ups consider swinging to be a style of cheating -- swinging allows you to use momentum to help yourself up. Military branches, such as the Marines, require recruits to perform dead-hang pull-ups as part of their physical fitness test. If you swing when you do pull-ups, the dead-hang version will be more challenging at first, but it will help you build up your strength and endurance.
Use a step or bench to climb up and grab the pull-up bar. Do not jump to grab the bar, as this initiates swinging. If you do have to jump up to the bar, wait until your body stops swinging before you start the exercise.
Cross your ankles and engage your abdominal muscles to stabilize your legs and core and reduce swinging. To engage your abs, pull your belly button into your spine.
Perform the pull-up exercise slowly. If you do the movement too quickly, you will start swinging. Take two counts to pull yourself up to the bar, pause for one count and take two counts to lower yourself back down.
Place a chair or other object under the bar. If you start to swing, set your feet lightly on the object to stop the motion. Once you stop swinging, lift your feet off the chair and then resume doing the pull-up exercise.
Consult a physician prior to starting any exercise program.