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  3. Exercises
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  5. Core & Abs
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  7. Sit Up On Stability Ball

Exercise guide

Sit Up On Stability Ball

  • Beginner
  • Compound
  • Rep-based
  • Waist

This exercise targets the rectus abdominis and obliques by utilizing the ball's curvature to increase the range of motion and challenge core stability. It provides a deeper stretch and more intense contraction compared to traditional floor sit-ups.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Sit Up On Stability Ball demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Abs
  • Obliques

Secondary

  • Erector spinae
  • Hip flexors

Equipment

  • Stability ball

Setup

  1. Sit on the stability ball with your feet flat on the floor, hip-width apart.
  2. Walk your feet forward slowly while leaning back until the ball is positioned under your lower back and mid-back.
  3. Place your hands lightly behind your head with elbows wide, or cross them over your chest.
  4. Position your body so your thighs and torso are roughly parallel to the floor.

How to do it

  1. Exhale and contract your abdominals to curl your upper body toward your knees, lifting your shoulder blades off the ball.
  2. Pause at the top of the movement for one second to emphasize the peak contraction.
  3. Inhale and slowly lower your torso back down over the curve of the ball, returning to the starting position.
  4. Maintain a controlled 2-1-2 tempo (2 seconds down, 1 second pause, 2 seconds up).

Form checklist

  • Keep your chin tucked slightly toward your chest to avoid neck strain.
  • Ensure the movement comes from your core, not by pulling on your head with your hands.
  • Keep your feet firmly planted and your glutes engaged to stabilize the ball.
  • Focus on 'curling' your ribs toward your pelvis rather than just hinging at the hips.

Pro tips

  • Take advantage of the ball's shape by allowing your spine to slightly extend over the curve at the bottom for a full abdominal stretch.
  • Keep your tongue pressed to the roof of your mouth to help stabilize the deep neck flexors and reduce strain.

Make it harder

  • Hold a medicine ball or weight plate against your chest to increase resistance.
  • Narrow your stance by bringing your feet together to decrease your base of support and increase the stability demand.

Frequently asked

What muscles does the sit up on stability ball work?
The sit up on stability ball primarily targets the abs and obliques, and also works the erector spinae and hip flexors as secondary muscles.
What equipment do you need for the sit up on stability ball?
The sit up on stability ball uses stability ball.
Is the sit up on stability ball good for beginners?
Yes. The sit up on stability ball 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

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

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