Exercises · waist

Jackknife Split Crunch

A crunch variation combining a V-up with a leg split to target the abs and hip flexors.

waistrectus abdominisbody weightintermediatecompound

Secondary muscles

hip flexorsobliquesadductors

How to do it

  1. Lie on your back with arms extended overhead and legs straight.
  2. Engage your core and simultaneously lift your torso and legs off the ground.
  3. As you rise, spread your legs into a split while reaching your hands toward your feet.
  4. Pause at the top, squeezing your abs.
  5. Lower your legs and torso back to the ground with control, bringing feet together.

Form cues

  • Keep core tight
  • Don't arch lower back
  • Lead with chest
  • Controlled split

Common mistakes

  • Swinging the legs
  • Using momentum
  • Arching the lower back

Breathing

Exhale when crunching up, inhale when lowering down.

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