AKA Concentric split jerk, bottom-up jerk, block jerk
The concentric jerk is a jerk variation that begins with the bar resting on blocks and removes the dip portion of the lift.
Set a bar on jerk blocks that places it at the height it would be in the bottom of your normal jerk dip. Position yourself in the jerk dip position under the bar with only enough pressure against the bar to ensure you’re in position and balanced.
Once you’ve set this position and the bar and your body are still, drive aggressively with the legs against the floor to accelerate the barbell upward. As you finish the extension of the legs, begin pushing against the bar with the arms, quickly lifting the feet and transitioning them into the split position, punching the arms into a locked-out overhead position. Secure and stabilize the bar overhead before recovering from the split into a standing position with the bar still overhead.
Avoid rocking into position or creating excessive tension against the bar prior to initiating the lift, as this reduces the effect—the point is to begin the lift from a dead stop with the bar supported entirely by the blocks.
The concentric jerk forces maximal rate of force development to improve the power of the jerk drive by eliminating any elastic contribution of the barbell or legs, and even any additional pre-tension that would be available in a pause jerk. Because it eliminates these things, it can also be used to train and reinforce a complete upward drive prior to the push under the bar. It can also be used as a jerk alternative when injury or pain the knees or elsewhere prevents the lifter from performing the dip phase of the jerk.
Sets of 1-3 reps are suggested with weights at 60% of more of the lifter’s maximum jerk. This lift can be used as a warm-up for jerks to encourage a more aggressive and complete drive, in addition to jerks, or as a substitute for jerks when training the specific elements it emphasizes is needed.
Concentric jerks can be performed behind the neck or as power variations.