You probably shouldn't do kipping pull-ups
There is perhaps no movement in modern fitness more divisive than the kipping pull-up. Christian Thibaudeau of T-Nation wrote,
Want to start an argument? Just bring up the topic of kipping pull-ups. Want to cause a fist fight? Expand the conversation to butterfly kipping pull-ups.
They're not as ridiculous as they look
I consider myself somewhat of a defender of kipping pull-ups. When people complain that it's not a strict pull-up, the answer is no kidding. Knocking a kipping pull-up for not being a strict pull-up is like knocking an Olympic jerk for not being a strict shoulder press. They're simply different movements with different purposes in mind; Crossfit popularized the exercise, and its prevalence in Crossfit WODs has given the public the mistaken impression that Crossfit doesn't train strict pull-ups. They do. Kipping is a progression from a strict pull-up. It requires precise timing and explosive movement, and it takes a fair bit of practice to master.
I'm also of the opinion that its 'risks' are greatly overstated. Not advisable for someone with shoulder injuries, sure; but dangerous for the rest of us? Hardly. At full extension in a regular kipping pull-up, the shoulders are indeed slightly extended behind the body — very similar to the Olympic snatch, and not fundamentally dangerous. At the top of the motion, the elbows are retracted at an angle similar to the stretch position in an incline press; again, not fundamentally dangerous. Anecdotally, there's not much evidence that people experience high injury rates with kipping pull-ups.
But seriously, don't do them
In gymnastics, kipping is a transitional movement. Gymnasts don't train kips with high reps, like athletes do in Crossfit. So why on earth would this transitional movement be regarded as an exercise at all? The exact answer is somewhat murky, but it seems to involve two components:
- The rules of Crossfit competitions only state that the competitor must pull their chin above the bar. The kipping pull-up is just an easier way to achieve that over multiple repetitions, and the Crossfit Games don't specifically forbid it.
- It develops anaerobic capacity and explosive power.
If you're into competitive Crossfit, then you have to do them. For better or worse, they've become standard. But aside from "Crossfit competitors do them", the rationale for doing them is pretty thin.
Yes, kipping pull-ups do develop anaerobic capacity. But there are safer and more effective ways to do this, like interval training on an air bike or with battle ropes. While kipping movements aren't dangerous per se, your risk of injury does increase greatly when you are doing high-skill movements under exhaustion.
Worse, there's no reason to think that kipping pull-ups offer any sort of valuable skill transfer. They require explosive power through the hips and shoulders, which is also essential for Olympic lifts; and the shoulder extension at the bottom is somewhat reminiscent of an Olympic snatch. But it's far more effective to simply practice the Olympic lifts if you want to get better at them, especially since a kip is more or less a loose 'swing', while Olympic lifts are done under extreme muscle tension and require immense core strength. Indeed, a strict pull-up, by developing the lats, is much more likely to improve your Olympic lifts.
That leaves one final possible reason to do kipping pull-ups: they're challenging and fun. If you enjoy doing them, then by all means do them. This a 100% legitimate as any — no different than doing lots of sprints, battle ropes, stair runs, kettlebell metcons, or any other type of high-intensity interval work (which, by the way, is exactly what kipping pull-ups are). There are lots of fun and unique ways we can push our bodies, and kipping pull-ups are just one of them. There are many safer and substantially more effective exercises for increasing anaerobic capacity, and kipping pull-ups are certainly not essential to any fitness program. You don't need them, and you probably shouldn't do them. But if you like them, have at it — just be prepared for the droves of onlookers who will tell you you're doing pull-ups wrong.