Exercise guide
Crunch Arms Straight
- Beginner
- Isolation
- Rep-based
- Waist
The straight-arm crunch increases the lever length of the upper body, placing significantly more tension on the rectus abdominis than a standard crunch. This variation is excellent for isolating the upper abdominals while discouraging the common mistake of pulling on the neck.
Reviewed by the Crucible team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on a mat 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 the floor with your palms facing up.
- Press your lower back firmly into the mat 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 locked straight and pinned next to your ears throughout the entire upward phase.
- Pause at the top for a one-second peak contraction, focusing on bringing your ribs toward your hips.
- Inhale as you slowly lower your torso back to the starting position with a controlled 2-second tempo.
Form checklist
- Keep your arms aligned with your ears; do not let them swing forward toward your knees.
- Maintain a small gap between your chin and chest to avoid neck strain.
- Ensure your lower back stays glued to the floor; do not lift into a full sit-up.
- Focus on 'curling' the spine rather than lifting the torso as a flat unit.
Pro tips
- To maximize muscle fiber recruitment, imagine you are trying to touch the wall behind you with your fingertips as you crunch upward.
- Exhale all of your air at the top of the movement to achieve a deeper contraction of the transverse abdominis.
Make it harder
- Hold a light weight plate or medicine ball between your hands while keeping the arms fully extended.
- Lift your feet off the floor and hold your legs in a tabletop position (90-degree bend) to increase core stability demands.
Frequently asked
- What muscles does the crunch arms straight work?
- The crunch arms straight primarily targets the abs, and also works the erector spinae as secondary muscles.
- What equipment do you need for the crunch arms straight?
- The crunch arms straight requires no equipment — just your body weight.
- Is the crunch arms straight good for beginners?
- Yes. The crunch arms straight is a beginner-friendly movement and a strong foundation to build on.