Just a Crossfit World editorial on chin ups from 6 Feb, 2011...
"Torn palms. What causes it? Usually, it is caused by high rep pull-up workouts done by folks who have to use a HUGE kipping movement to perform a pull-up. The kipping pull-up is a fantastic gymnastic movement to get you from below the bar to chin over the bar. In gymnastics, it is performed all the time.... but not over and over again. A huge kip done in high reps is likely going to tear up your palms. If you get stronger at pull-ups, you won't have to use such a violent kip to get over the bar. The huge kipping pull-up is, in all actuality, a cheat to get a pull-up. No offense to anyone, but the fact of the matter is that if you do a kip this huge, you do not have the strength to do a solid pull-up repeatedly."
(this is how this whole thread got started. I made a comment that if I had done chin-ups like these "kips" in the Army, they wouldn't have counted. But you know, you do have to start somewhere....)