Ez-bar Skullcrusher vs Jm Press

Compare target muscles, equipment, difficulty, movement type, and secondary muscles for Ez-bar Skullcrusher and Jm Press.

Get comparison link

Comparison link

Select the link and use your device's Copy command.

EZ-Bar Skullcrusher vs JM Press — you want the right triceps move for size, strength, or limited gear. In this comparison I’ll show you how the two exercises load the triceps differently, which secondary muscles join the work, and the technical cues you need to perform each safely. You’ll get clear winners for hypertrophy, strength, beginners, and home setups, plus rep ranges, common mistakes, and simple progressions so you can pick the lift that fits your goals and training phase.

Exercise A

Ez-bar Skullcrusher

Target Triceps

Equipment Ez-barbell

Body Part Upper-arms

Difficulty Intermediate

Movement Isolation

Secondary Muscles

Forearms

Exercise B

Jm Press

Target Triceps

Equipment Barbell

Body Part Upper-arms

Difficulty Advanced

Movement Compound

Secondary Muscles

Chest Shoulders

Muscles used

Listed target and secondary muscles, shown on the body. Locations, not activation or strength scores.

Target
Secondary
Not highlighted

Ez-bar Skullcrusher

Front

Back

Target: Triceps
Secondary: Forearms

Jm Press

Front

Back

Target: Triceps
Secondary: Chest, Shoulders

Not shown on diagram: Shoulders. These labels do not identify a precise region on this map.

Grey does not mean a muscle is unused. The diagrams show only the mapped catalogue labels.

Attribute	Ez-bar Skullcrusher	Jm Press
Target Muscle	Triceps	Triceps
Body Part	Upper-arms	Upper-arms
Equipment Different	Ez-barbell	Barbell
Difficulty Different	Intermediate	Advanced
Movement Type Different	Isolation	Compound
Secondary Muscles Different	Forearms	Chest, Shoulders

Visual Comparison

An illustrative 1–10 profile derived from catalog difficulty, equipment, and listed-muscle fields—not measured performance or muscle activation.

Key Differences

Equipment differs: Ez-bar Skullcrusher uses Ez-barbell, while Jm Press requires Barbell.
Ez-bar Skullcrusher is an isolation exercise, while Jm Press is a compound movement.
Difficulty levels differ: Ez-bar Skullcrusher is intermediate, while Jm Press is advanced.

Muscle comparison

Shared target muscles

Both exercises primarily drive elbow extension and heavily load the triceps brachii. The EZ-Bar Skullcrusher is a true isolation pattern: the bar travels in an arc with the moment arm focused at the elbow, so nearly all work comes from the triceps (especially long and medial heads). The JM Press still targets the triceps but shares force with shoulder horizontal flexion, so a smaller percentage of total load is pure elbow extension compared with skullcrushers.

Secondary muscle differences

Skullcrushers keep shoulder position static, so forearms and wrist stabilizers are the main secondary recruits. The JM Press is a compound pattern that brings the chest and anterior deltoids into play; chest and shoulder contribution can account for roughly 15–30% of force depending on bar path and elbow flare. JM Press also requires more scapular and core stability because the load transfers through the shoulder complex.

Muscle involvement analysis

Skullcrushers produce peak triceps tension when the elbow passes ~90° of flexion to full extension, emphasizing a pure elbow-extension moment and maximizing time under tension. JM Press blends elbow extension with horizontal adduction, so the force vector shifts anteriorly; the triceps still produce extension torque but with reduced moment arm at the elbow and greater concurrent shoulder moment, changing activation timing and increasing integrated chest/delt EMG during the concentric.

Equipment and setup

Ez-bar Skullcrusher: setup

EZ-Bar Skullcrusher requires an EZ-bar (or straight bar/dumbbells as a variant), a flat bench, and a rack or floor space for safe setup. You can substitute dumbbells if no EZ-bar is available.

Jm Press: setup

JM Press requires a barbell, a flat bench, and ideally a spotter or safety pins in a rack because the movement blends press and extension and is often loaded heavier. Good wrist mobility and a secure grip are important.

Access and practicality

EZ-Bar Skullcrusher — it’s more adaptable for most gyms and home setups because you can use an EZ-bar, straight bar, or dumbbells. JM Press needs a barbell and is more setup- and skill-dependent, making it less accessible for casual lifters.

Learning and progression

Learning the movements

EZ-Bar Skullcrusher is intermediate: the movement pattern is single-joint and easier to teach—keep the upper arm steady and extend at the elbow. JM Press is advanced: you must coordinate bar path, elbow angle, and shoulder position to avoid stress on the elbow and shoulder.

Progression considerations

JM Press offers greater raw loading potential and direct transfer to pressing strength because it lets you handle heavier absolute weights and integrates multiple joints. Skullcrusher offers excellent progression for hypertrophy using tempo, higher volume (8–15 reps), and variations (incline, decline, dumbbell).

Limitations and precautions

Relative injury risk is higher with JM Press due to heavier loads and combined joint stresses on the elbows, wrists, and anterior shoulder if technique is sloppy. Skullcrushers pose notable elbow-tendon risk when ego-loading or allowing excessive elbow flare; controlled range of motion and moderate loading (6–12 reps for strength/hypertrophy) reduce risk.

Pros & Cons

Ez-bar Skullcrusher

+ Pros

Direct triceps isolation maximizes time under tension for muscle growth
Simple technical cues: stable upper arm, extend at the elbow, control negative
Easily modified with dumbbells or angled benches to shift long-head emphasis
Lower overall systemic fatigue compared with compound presses

− Cons

High compressive stress on the elbow and risk to tendons with heavy loads
Limited transfer to compound pressing strength (bench press carryover is small)
Requires good shoulder control to keep upper arm position and avoid flaring

Jm Press

+ Pros

Compound pattern allows heavier loading and better carryover to bench strength
Recruits chest and anterior deltoid for a multi-joint stimulus
Shorter range of motion at the elbow reduces extreme end-range tendon stress
Efficient: trains triceps plus pressing mechanics in one movement

− Cons

Technically demanding — poor setup increases shoulder/elbow strain
Less pure triceps isolation; chest/delts can dominate if bar path is wide
Requires barbell and safer setup (spotter or rack) when heavy

When Each Exercise Wins

For muscle hypertrophy: EZ-Bar Skullcrusher

Skullcrushers concentrate load at the elbow and maximize time under tension, letting you target the triceps long and medial heads with strict form and higher rep ranges (8–15). Use controlled 2–3 second eccentrics and finish sets with partials to increase local stimulus.

For strength gains: JM Press

JM Press allows heavier absolute loads and trains the combined elbow-extension and pressing pattern, which transfers better to bench press strength. Loading in the 3–6 rep range with progressive overload produces greater neural and force adaptations.

For beginners: EZ-Bar Skullcrusher

The isolation pattern is easier to learn—focus on keeping the upper arm stationary and extending at the elbow. It builds triceps strength and muscle control before adding complex multi-joint presses like the JM Press.

For home workouts: EZ-Bar Skullcrusher

Skullcrushers can be performed with an EZ-bar, straight bar, or two dumbbells and a bench, making them more flexible for limited equipment. JM Press needs a barbell and safer setup if you want to push heavy.

Frequently Asked Questions

Can I do both EZ-Bar Skullcrusher and JM Press in the same workout?

Yes. Start with JM Press as your compound movement when you’re fresh to capture heavy loading (3–6 reps), then use EZ-Bar Skullcrushers as an isolation finisher for 8–15 reps to increase time under tension and metabolic stress.

Which exercise is better for beginners?

EZ-Bar Skullcrusher is better for most beginners because it isolates the elbow extension pattern and is easier to coach. Mastering strict skullcrusher form builds triceps control before progressing to the more complex JM Press.

How do the muscle activation patterns differ?

Skullcrushers produce a pure elbow-extension moment with peak tension around 90° of elbow flexion to full extension, emphasizing triceps long and medial heads. JM Press blends elbow extension with horizontal shoulder flexion, shifting some activation to chest and anterior deltoids and altering the timing of peak triceps torque.

Can JM Press replace EZ-Bar Skullcrusher?

JM Press can replace skullcrushers if your goal leans toward strength and pressing transfer, but it won’t isolate the triceps as effectively. For maximal triceps muscle growth, keep skullcrushers or another isolation movement in your program.

Comparison Summary

Choose the EZ-Bar Skullcrusher when your priority is targeted triceps muscle growth and clean isolation work. Its elbow-focused moment arm and controllable range of motion make it ideal for 8–15 rep sets, tempo work, and finishing your upper-arm routine. Pick the JM Press when you want multi-joint overload and direct transfer to pressing strength—load it heavier for 3–6 reps and use it as a compound triceps/press accessory. Program both: use skullcrushers for dedicated hypertrophy blocks and JM Presses in strength phases to build absolute pressing power and shoulder-chest integration.

Exercise instructions

Steps from the exercise catalogue. Read the full sequence before starting.

Ez-bar Skullcrusher

Using a close grip, lift the EZ bar and hold it with your elbows in as you lie on the bench. Your arms should be perpendicular to the floor. This will be your starting position.
Keeping the upper arms stationary, lower the bar by allowing the elbows to flex. Inhale as you perform this portion of the movement. Pause once the bar is directly above the forehead.
Lift the bar back to the starting position by extending the elbow and exhaling.

Read remaining steps for Ez-bar Skullcrusher

Repeat.

Jm Press

Start the exercise the same way you would a close grip bench press. You will lie on a flat bench while holding a barbell at arms length (fully extended) with the elbows in. However, instead of having the arms perpendicular to the torso, make sure the bar is set in a direct line above the upper chest. This will be your starting position.
Now beginning from a fully extended position lower the bar down as if performing a lying triceps extension. Inhale as you perform this movement. When you reach the half way point, let the bar roll back about one inch by moving the upper arms towards your legs until they are perpendicular to the torso. Tip: Keep the bend at the elbows constant as you bring the upper arms forward.
As you exhale, press the bar back up by using the triceps to perform a close grip bench press.

Read remaining steps for Jm Press