Long Arm Crunch
The long arm crunch is a floor ab exercise in which you curl your shoulders off the floor with your arms held straight overhead beside your ears. Holding the arms overhead makes the curl harder than a standard crunch, and it works the rectus abdominis and the obliques.
Also called: Extended Arm Crunch, Arms Extended Crunch, Overhead Arm Crunch, Straight-Arm Crunch · Equipment: bodyweight · Pattern: isolation
Step by step
- Lie on your back with your knees bent and your feet flat on the floor, hip-width apart.
- Stretch your arms straight overhead so your upper arms sit beside your ears, hands together or shoulder-width apart.
- Breathe out and brace, keeping your low back on the floor.
- Curl your ribs towards your hips so your head, arms and shoulder blades lift off the floor together.
- Keep your arms in line with your ears as you curl; they rise with your upper body, not ahead of it.
- Pause briefly at the top, then uncurl slowly until your shoulder blades touch the floor.
- Repeat for the set, then bring your arms down to your sides to finish.
- Arms stay beside your ears
- Curl your ribs towards your hips
- Chin slightly tucked
- Low back stays on the floor
- Slow on the way down
In VALDA, these cues are one tap away on the exercise while you train.
What it trains
| Muscle | Role | Evidence |
|---|---|---|
| Rectus abdominis | Prime mover | C |
| Obliques (internal/external) | Secondary | C |
| Hip flexors | Stabiliser | D |
| Latissimus dorsi | Stabiliser | D |
Evidence grades: A = strong research base · B = good · C = limited · D = coaching consensus.
What goes wrong, and the fix
Swinging the arms forward
Fix: Keep your upper arms beside your ears for the whole rep.
Leading with the head
Fix: Tuck your chin slightly and lift your head, arms and shoulders as one piece.
Sitting all the way up
Fix: Lift only until your shoulder blades clear the floor.
Low back arching as the arms go overhead
Fix: Breathe out and flatten your low back before each rep.
Dropping back to the floor
Fix: Take about two seconds to uncurl.
What the research says
Muscle growthGeneral fitnessEndurance
- Muscle activity — In an EMG comparison of 13 ab exercises, the long arm crunch produced about 19% more rectus abdominis activity and 26% more oblique activity than the traditional crunch. EMG measures activity, not growth.
- Load — Research finds muscle growth is similar across a wide range of loads when sets are hard, and lighter, higher-rep work favours muscular endurance. Holding a light plate in the hands is a common next step.
- Volume — Research links more weekly sets for a muscle to more growth, with diminishing returns.
Swap it mid-workout
With VALDA Pro, FLEX offers alternatives like these when you swap an exercise mid-workout.
Log the long arm crunch in VALDA, with these cues one tap away while you train and your history for it in one place.
General information about exercise technique, not medical advice. If you have an injury or a health condition, your healthcare provider is the right person to ask.