The kipping pull up is a gymnastic-oriented move that has been most recently popularized for the strength and conditioning world thanks to CrossFit. It’s a way to get more repetitions in for the pull up, especially if your workouts are being timed. They begin with a coordinated, rhythmic body swing that helps propel the body upward over the bar using momentum. If pull ups are to be viewed as a back exercise (which is something most of the strength training community tends to agree upon), then kipping pull ups are a good way to accomplish very little. The body’s assistance to the movement takes away from any back isolation, and the lift becomes a cardio nightmare. Starting your learning curve for pull ups off with this method can set a lifter on the wrong track, and have him forego proper shoulder blade mechanics essential to proper and safe pulling. Moreover, a closer look at the bottom phase of the kipping pull up shows plenty of injury risk to the shoulder capsule due to the exaggerated shoulder hyperflexion that occurs before each pull. I’ll safely speculate that a weaker, less trained lifter would be even more susceptible to getting hurt compared to one with a stronger shoulder girdle. Instead, stick with normal pullups. If they get redundant, change your grip, tempo, and rest interval.