Kip Pull Up

This type of pull up is becoming more and more popular with Crossfit type workouts. Initiate the motion (from a dead hang) by swinging torso away from bars, then kicking knees up and forward. Use the momentum to pull up and into the bar with chin finishing higher than your hands. The advantage to doing this is that mechanically it is easier to perform the lift with momentum and the use of more muscles (via the knee up). I would caution however, that it is easy to roll your shoulders forward as you pull up. This is particularly hard on the joint. I like to see people use this type of movement as a stepping stone toward a traditional pull up that would finish with knees bent (feet behind hips), lower back arched, shoulders rolled back, with the chest and eyes up.