Exercise guide
Long Arm Crunch
- Beginner
- Isolation
- Rep-based
- Waist
The long arm crunch increases the lever length of a standard crunch, significantly increasing the challenge to the upper rectus abdominis. By extending the arms overhead, you create more resistance for the core to overcome without needing external weights.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back with your knees bent and feet flat on the floor, hip-width apart.
- Extend your arms straight back behind your head, keeping them parallel to each other with palms facing up.
- Press your lower back firmly into the floor to eliminate any arch in your spine.
How to do it
- Exhale and slowly lift your head, shoulders, and upper back off the floor by contracting your abs.
- Keep your arms straight and locked in line with your ears throughout the entire upward movement.
- Pause for one second at the peak of the contraction, squeezing your ribs toward your hips.
- Inhale as you slowly lower back to the starting position, maintaining tension in the core.
Form checklist
- Keep your arms glued to your ears; do not let them swing forward to create momentum.
- Focus on lifting the shoulder blades off the floor rather than just bending the neck.
- Ensure your lower back stays pressed into the mat throughout the exercise.
- Maintain a small gap between your chin and chest to avoid neck strain.
Pro tips
- Think about 'shortening' the distance between your sternum and belly button to maximize muscle fiber recruitment.
- Move with a 2-1-2 tempo (2 seconds up, 1 second hold, 2 seconds down) to eliminate momentum and increase time under tension.
Make it harder
- Hold a light weight plate or small dumbbell between your hands while keeping the arms extended.
- Perform the movement with your legs lifted in a tabletop position or extended straight up at a 90-degree angle.
Frequently asked
- What muscles does the long arm crunch work?
- The long arm crunch primarily targets the abs and obliques, and also works the erector spinae as secondary muscles.
- What equipment do you need for the long arm crunch?
- The long arm crunch requires no equipment — just your body weight.
- Is the long arm crunch good for beginners?
- Yes. The long arm crunch is a beginner-friendly movement and a strong foundation to build on.