Home · Exercise Library · Core · Star Crunches

Star Crunches

Star crunches start from a wide X position on your back and bring one hand across to the opposite foot, folding the trunk diagonally. Maddy programs them when a client needs oblique work that also grooves the cross-body pattern used in throwing, running, and rotation. Coached by Maddy (NASM-CPT) — these are the exact form cues he gives on every client's first week.

Muscles worked

Obliques Abs · rectus abdominis Deep core · transverse abdominis

Sets & reps by goal

GoalSets × RepsRest
Strength3 × 5-6 slow reps per side90 s
Muscle3 × 9-12 reps per side60 s
Endurance2-3 × 18-27 total alternating reps30-45 s

Rep ranges per Helms 2014 · Schoenfeld 2016.

Level — Beginner

Beginner-to-intermediate; the wide starting position makes each rep honest but also makes cheating obvious.

Proper form — 5 cues

  1. Set up in a wide X — arms and legs spread, low back resting on the floor.
  2. Exhale and lift the shoulder blade off the floor as your hand reaches across.
  3. Bring the opposite leg up straight to meet the hand near the midline.
  4. Lower both limbs back to the X with control — no flopping.
  5. Alternate sides and keep the non-working arm and leg resting wide.

Breathing: Exhale hard as hand and foot come together, inhale as you open back to the X.

The 3 mistakes Maddy corrects most

Reaching with the arm while the shoulder blade stays glued to the floor.. If the torso never flexes, the obliques never contract — it becomes an arm wave, not a crunch. Fix: Make 'shoulder blade off the floor' the rep standard; the hand touching the foot is just the finish line.
Swinging the leg up with momentum to meet a lazy torso.. The kick uses hip flexor momentum and robs the diagonal trunk fold of its work. Fix: Raise the leg at the same controlled speed as the torso — they should meet in the middle, both working.
Yanking the neck forward with the reaching arm's momentum.. Neck strain shows up quickly and shifts your attention off the abs. Fix: Keep a fist-sized gap under the chin and lead the movement from the ribcage.

Common questions

Can beginners do star crunches?

Yes, with two adjustments. Bend the rising knee so the foot is easier to reach, and slow the pace so each rep is a deliberate fold rather than a flail. If your low back arches off the floor as the leg lowers, do not lower it all the way — stop where your back stays down. Most beginners are doing clean full reps within two to three weeks.

Star crunches vs bicycle crunches — which is better for obliques?

Both train the obliques through cross-body flexion; the difference is rhythm. Bicycles are continuous and cyclical, which makes them easy to rush and cheat. Star crunches reset to a wide X every rep, which forces a fuller range and a distinct start and finish. Maddy tends to use star crunches for quality-focused sets and bicycles for higher-rep conditioning blocks — they earn different jobs, not a ranking.

How many star crunches should I do?

Start with 3 sets of 8-10 per side, done slowly, two or three times a week inside your core block. Progress by adding a rep per side each week or by pausing for a second at the top where hand meets foot. When 12 clean reps per side feel controlled, move to the advanced double-sided version rather than endlessly adding volume.

Related exercises

Harder: Star Crunches (Advanced)

Bicycle KicksObliques Bicycle Kicks (Modified)Obliques Cross Knee to Elbow PulseObliques Downward Dog Cross Knee to Elbow TouchObliques Downward Dog Knee to Elbow TouchObliques

Browse: All core exercises · All bodyweight exercises · Full exercise library

This is one exercise. Your plan is the other 99%.

Maddy hand-builds training around your exact body — schedule, recovery, injuries, food culture. It starts with a 3-minute scan.

Start My Body Scan → 11 questions · 3 min · free · no card yet