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  7. Sit-Up With Chair Assisted

Exercise guide

Sit-Up With Chair Assisted

  • Intermediate
  • Compound
  • Rep-based
  • Waist

This beginner-friendly variation uses a chair to elevate the legs, which stabilizes the pelvis and isolates the abdominal muscles by reducing hip flexor involvement. It is highly effective for building foundational core strength while protecting the lower back.

Reviewed by the Crucible team · Updated June 2026

Watch the Sit-Up With Chair Assisted demonstrationGuided video and your full workout live in the Crucible app.

Muscles worked

Primary

  • Abs

Secondary

  • Erector spinae

Equipment

  • Dumbbell

Setup

  1. Lie on your back on a mat with a sturdy chair or bench positioned at your feet.
  2. Place your calves and heels on the seat of the chair so your knees and hips are bent at approximately 90-degree angles.
  3. Cross your arms over your chest or place your fingertips lightly behind your ears without interlocking your fingers.

How to do it

  1. Exhale as you contract your abs to peel your head, shoulders, and upper back off the floor toward your knees.
  2. Lift until your shoulder blades are clear of the mat, focusing on shortening the distance between your ribs and hips.
  3. Inhale as you slowly lower your torso back to the starting position using a controlled 2-second eccentric phase.
  4. Keep your lower back in contact with the floor throughout the initial phase of the lift.

Form checklist

  • Keep your chin tucked slightly to maintain a neutral neck position.
  • Avoid pulling on your head or neck with your hands.
  • Ensure your legs remain relaxed on the chair to minimize hip flexor assistance.
  • Maintain a smooth, controlled motion without using momentum.

Pro tips

  • Imagine sliding your ribcage down toward your belly button to maximize abdominal engagement.
  • Pause for one second at the top of the movement to emphasize the peak contraction of the rectus abdominis.

Make it harder

  • Hold a light weight plate or medicine ball against your chest.
  • Perform the movement with your arms extended straight overhead to increase the lever length and resistance.

Frequently asked

What muscles does the sit-up with chair assisted work?
The sit-up with chair assisted primarily targets the abs, and also works the erector spinae as secondary muscles.
What equipment do you need for the sit-up with chair assisted?
The sit-up with chair assisted uses dumbbell.
Is the sit-up with chair assisted good for beginners?
The sit-up with chair assisted is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.

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 this with a plan, not guesswork

Crucible builds the sit-up with chair assisted into a precise program around your body, equipment, location, and time.

Download on the App Store