There is a lot of discussion on the Internet about the Kettlebell Swing as a viable technique to improve strength, endurance, power, etc. For the most part the majority of trainers (and their clients) agree that the Swing is a valuable tool in their training toolbox. Where the disagreement starts is in deciding which Swing to use. Those who have been exposed to or trained by an RKC (Russian Kettlebell Certified instructor) will recommend the Russian Swing. Those who have been exposed to Kettlebells via Crossfit will invariably recommend the American Swing. So who is right? Well, in my humble opinion, they both are - as long as they are talking about the same technique - and for the most part they aren't. Let's take a moment to define the two techniques and maybe even through in a picture or two for clarification.
The Russian Swing
The Russian Swing (Kettlebell Swing) is the foundation that the RKC program is built upon. The Russian Swing (RS) is characterized by an explosive extension of the hips that drives the kettlebell to approximately chest-height (but in some cases lower; depending on the weight of the kettlebell). Synchronized breathing and management of full-body tension are also characteristics of the RS but those elements are less controversial that the height the kettlebell attains at the completion of the Swing. Because the Swing only goes to chest-high it is deemed "incomplete" or "inefficient" for training purposes by most trainers in the Crossfit community.
The American Swing
The American Swing, which is credited by most as a product of Crossfit, is a kettlebell "Swing" that goes overhead. The longer stroke of this Swing gives it a completely different feel than that of the Russian Swing. Unfortunately, most people view the American Swing (AS) as just that, a Swing - in reality it is anything but a Swing. The trajectory of a RS is an arc that terminates at chest-height then returns to between the legs (don't get me started on the backswing variables!). The AS trajectory is more of a "J" that comes from between the legs, hugs the torso and then is explosively projected overhead before returning between the legs along the same path. Many people have commented that is looks like a "two-hand snatch" and that's the term I first encountered when I saw this technique over a decade ago (Russian SAMBO players fresh from deployment with scars to proves it!).
The RS is an excellent starting point for beginner to intermediate Kettlebell users to develop and then fine tune their hip snap and hinging technique. Because of the relatively low height of the RS, individuals with shoulder injuries or mobility issues can do this technique without fear of doing additional injury. The AS is a great technique for intermediate to advanced Kettlebell users to fine tune their hip snap and to develop solid transitional techniques from the ballistic pull to press or punch through. With it's dynamic overhead extension it is only safe for people who have healthy, mobile shoulders and those who can effectively manage the load overhead without compromising the thoracic spine in the process.
They are both excellent techniques and have their place in any Kettlebell or Crossfit workout. Just be sure to spend some time learning how to do them both - yes they really are very different techniques - and you will benefit from them in a myriad of ways.