Exercise guide
Sit-Up With Arms On Chest
- Beginner
- Compound
- Rep-based
- Waist
This variation targets the rectus abdominis and hip flexors while minimizing momentum by crossing the arms over the chest. It builds foundational core strength and improves spinal flexion control.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on a mat with knees bent at approximately 90 degrees and feet flat on the floor.
- Cross your arms over your chest, placing your hands on opposite shoulders.
- Tuck your chin slightly toward your chest to maintain a neutral neck position.
How to do it
- Exhale and engage your core to lift your upper body off the floor, curling your spine until your elbows reach your thighs.
- Maintain a controlled 2-second tempo on the way up, focusing on abdominal contraction.
- Inhale as you slowly lower your torso back to the starting position, unrolling your spine one vertebra at a time.
Form checklist
- Keep your feet pinned to the floor; do not let them lift as you rise.
- Avoid leading with your head or neck to prevent strain.
- Ensure your lower back touches the mat before your shoulders during the descent.
- Keep your arms firmly crossed against your chest throughout the set.
Pro tips
- Visualize your ribcage pulling down toward your pelvis to maximize rectus abdominis engagement.
- Pause and squeeze your abs at the top of the movement to eliminate any reliance on momentum.
Make it harder
- Slow the eccentric (lowering) phase down to 4 seconds to increase time under tension.
- Perform the exercise on a decline bench to increase the range of motion and gravity's resistance.
Frequently asked
- What muscles does the sit-up with arms on chest work?
- The sit-up with arms on chest primarily targets the abs and obliques, and also works the serratus anterior as secondary muscles.
- What equipment do you need for the sit-up with arms on chest?
- The sit-up with arms on chest requires no equipment — just your body weight.
- Is the sit-up with arms on chest good for beginners?
- Yes. The sit-up with arms on chest is a beginner-friendly movement and a strong foundation to build on.