Dumbbell Single Arm Starfish Crunch

Muscles worked

Setup

1. Lie flat on your back with your arms and legs spread wide to form an 'X' shape on the floor.
2. Hold a light dumbbell in your right hand with your arm extended straight out from your shoulder.
3. Keep your left arm and both legs resting on the mat, ensuring your lower back is in a neutral position.

How to do it

1. Exhale and lift your right arm and left leg simultaneously, crunching your upper torso upward to reach the dumbbell toward your left foot.
2. Inhale as you lower your arm and leg back to the floor with a controlled 2-second tempo.
3. Maintain a slight tuck in your chin to protect your neck as you lift your shoulder blade off the mat.
4. Perform all repetitions on one side before switching the dumbbell to the opposite hand and repeating with the opposite leg.

Form checklist

• Keep the working arm and leg as straight as possible to maximize core tension.
• Ensure the non-working arm stays flat on the floor to provide a stable base.
• Press your lower back firmly into the ground as you return to the starting position to prevent arching.
• Avoid using momentum or swinging the weight; focus on a slow, deliberate crunch.

Pro tips

• Focus on the 'diagonal' connection by visualizing your ribcage pulling toward your opposite hip bone.
• Squeeze your quadriceps and flex your foot to keep the leg rigid, which helps better engage the hip flexors and lower abdominals.

Make it harder

• Hover your heels and the dumbbell two inches off the floor between repetitions to keep the core under constant tension.
• Slow the eccentric (lowering) phase to 4 seconds to increase the time under tension.

Frequently asked

What muscles does the dumbbell single arm starfish crunch work?

The dumbbell single arm starfish crunch primarily targets the abs and obliques, and also works the erector spinae and serratus anterior as secondary muscles.

What equipment do you need for the dumbbell single arm starfish crunch?

The dumbbell single arm starfish crunch uses dumbbell.

Is the dumbbell single arm starfish crunch good for beginners?

Yes. The dumbbell single arm starfish crunch is a beginner-friendly movement and a strong foundation to build on.

Related exercises

• 3/4 Sit-UpBeginner · abs and obliques
• 45 Degree Bicycle Twisting CrunchIntermediate · abs and obliques
• 45 Degree Lean Back Alternate Knee RaiseBeginner · abs and obliques
• 45 Degrees Arms PlankIntermediate · abs, deltoids, obliques, and pectorals