The concentric power jerk is a power jerk that begins with the bar resting on blocks and removes the dip portion of the lift.
 
Set the bar on jerk blocks that places it at the height it would be in the bottom of your normal jerk dip. Position yourself under the bar as you would be in the bottom of your dip and brace your trunk.
 
From a dead stop, drive aggressively with the legs against the floor to complete a power jerk as you would otherwise.
 
Notes
The lift can be taken from the pins of a power rack instead of jerk blocks.
 
Purpose
The concentric power 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 most of the 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. The power receiving position simplifies the lift, but also requires the lifter create more height on the bar and be more precise with balance and bar positioning overhead.
 
Programming
Sets of 1-3 reps are suggested with weights at 50% of more of the lifter’s maximum power jerk. This lift can be used as a warm-up for power jerks or split jerks to encourage a more aggressive and complete drive, in addition to power jerks, or as a substitute for power jerks when training the specific elements it emphasizes is needed.     
 
Variations
Concentric power jerks can be performed behind the neck.