DB Skullcrushers:
– Initialize your position by sitting on the end of a bench with a DB in each hand and resting on your thighs. Note: this can be done with various bench angles but we will use flat for this breakdown.
– Begin by carefully rolling your body back into a supine position on the bench. Simultaneously, maneuver the DBs from your thighs to over your chest with elbows locked out and arms perpendicular to the floor. Take a moment to stabilize your body and the load.
– Your wrists should be neutral, feet flat on the floor, low back slightly arched, scaps depressed and slightly retracted, and head resting on the bench.
– Start the eccentric by flexing at the elbows and allowing the DBs to descend under control. Your shoulders should move through subtle, but limited, flexion to create more space for the ROM while also ensuring relatively fixed upper arms.
– Continue this controlled descent until elbow flexion has been exhausted. This will typically be indicated by the resistance curve falling off steeply or the DBs running into a barrier.
– Once the terminal end point of the ROM has been achieved, reverse the motion into the concentric and mirror the pattern through elbow extension back to full lockout.
– When the set is over, carefully control the DBs back to your thighs and return to a seated position.
DB JM Press:
– Initialize your position by sitting on the end of a bench with a DB in each hand and resting on your thighs. Note: this can be done with various bench angles but we will use flat for this breakdown.
– Begin by carefully rolling your body back into a supine position on the bench. Simultaneously, maneuver the DBs from your thighs to over your chest with elbows locked out and arms perpendicular to the floor. Take a moment to stabilize your body and the load.
– Your wrists should be neutral, feet flat on the floor, low back slightly arched, scaps depressed and slightly retracted, and head resting on the bench.
– Start the eccentric by flexing at the elbows AND extending at the shoulders thus allowing the DBs to descend under control. Elbow flexion and shoulder extension should be matched 1:1 through the eccentric with the elbows translating inferior (i.e. moving down the body). Maintain strong wrists throughout.
– Continue this controlled descent until the head of the DBs contact your anterior delts.
– Once the terminal end point of the ROM has been achieved, reverse the motion into the concentric and mirror the pattern through elbow extension and shoulder flexion back to full lockout.
– When the set is over, carefully control the DBs back to your thighs and return to a seated position.
– Note: the name “JM Press” is a misnomer; the movement is still an extension, and pressing (using the pecs) should be avoided as much as possible.
Key Similarities:
– Elbow extension pattern with emphasis on triceps isolation
– Ideal rep range is between 10-20 reps
– Primarily used to increase triceps hypertrophy (through mechanical overload) and pressing strength (through building the lockout)
– The patterns tend to be harsh on elbows but the modality (DBs>barbell/EZ bar) and the grip (neutral>pronated) mitigate a lot of the sheering force
– Each can benefit from many of the same intensity techniques (i.e. load drop sets, cluster sets, myoreps, etc)
– Both can be used strategically within supersets and circuits due to the lower risk of acute injury
Key Differences:
– SCs have a relatively fixed upper arm position while JMPs emphasize downward translation of the elbows through the eccentric.
– JMPs are more mechanically favorable for the triceps and thus allow more load to be used compared to SCs.
– JMPs are more specific to presses and correlate more strongly with increasing strength. SCs take the triceps through a more full ROM and loaded stretch which correlates more strongly with muscle growth.
– JMPs require more ancillary support from the anterior delts while SCs place a greater demand on the lats.
– SCs tend to be easier to conceptually grasp. There is often a learning curve associated with JMPs. For these reasons, JMPs might be better suited for intermediate and advanced trainees.
Primary Use Case for DB Skullcrusher:
-Hypertrophy of the Triceps
Primary Use Case for DB JM Press:
-Increasing Pressing Strength
-Hypertrophy of the Triceps