Starfish Crunch

Muscles worked

Setup

1. Lie flat on your back on a mat with your arms and legs spread wide to form an 'X' shape.
2. Position your arms at a 45-degree angle above your shoulders and your legs at a 45-degree angle from your hips.
3. Press your lower back firmly into the floor to engage your core and eliminate any arch in the spine.

How to do it

1. Exhale and lift your right arm and left leg simultaneously, peeling your upper back off the floor to reach across your body.
2. Touch your right hand to your left shin or toes, focusing on the contraction in your midsection and obliques.
3. Inhale as you slowly lower both limbs back to the starting position with a controlled 2-second tempo.
4. Repeat the movement on the opposite side (left arm to right leg) and continue alternating sides for the duration of the set.

Form checklist

• Keep your lower back in contact with the mat as you lower your limbs to protect the spine.
• Lead the movement with your chest and shoulders rather than pulling on your neck.
• Maintain a slight bend in the knees if your hamstrings feel tight to ensure the focus remains on the abs.
• Avoid using momentum to swing your limbs up; ensure the abdominal muscles are doing the lifting.

Pro tips

• Visualize pulling your ribs toward the opposite hip bone to maximize oblique engagement during the reach.
• Keep the non-moving arm and leg pressed firmly into the floor to provide a stable anchor for the rotation.
• Pause for a split second at the top of the movement to emphasize the peak contraction of the rectus abdominis.

Make it harder

• Keep all four limbs hovering 2-3 inches off the floor between repetitions to maintain constant tension on the core.
• Hold the peak contraction at the top for 2-3 seconds before lowering with an even slower eccentric phase.

Frequently asked

What muscles does the starfish crunch work?

The 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 starfish crunch?

The starfish crunch requires no equipment — just your body weight.

Is the starfish crunch good for beginners?

Yes. The 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