What is a kettlebell "jerk"?
The kettlebell jerk is a movement that utilizes the momentum generated by the legs to bring the bells from the rack position to the overhead position. While your arms and shoulders are working to stabilize, they should not be pushing the bells into the overhead position (or the timing will be off). The quicker the launch and the more relaxed the triceps are, the faster the lifter will be able to jerk without feeling muscular fatigue of the upper body.
Here is a clip of one of my training sets, exemplifying 19-21rpm with 2x14kg kettlebells. Perfecting technique with light bells will greatly improve efficiency at higher weights. You don't always have to train heavy!!!
For a full video tutorial on the kettlebell jerk, click here.